Edible Terrariums (chocolate Cake in Jar)




About: Once a mechanical and materials engineer that worked on rockets, I am now a stay-at-home mom to three incredible children. I also teach chess to elementary students after school once a week. I first got ho...

This ible came out of a need for "last-minute" Christmas gifts when my first choice fell through. I ordered terrarium parts online for my kids' teachers (all nine of them) in early November, and they still have yet to reach my house by mail. I didn't want to re-buy the terrarium parts elsewhere, so what could I do instead? I usually make edible goodies for the teachers and staff at the school this time of year, so I thought about changing the real terrariums into edible versions using Ball mason jars. I had a vision of going beyond the cute edible to a "no-way-that-is-fake-it-is-so-realistic" edible version!

Where it was possible, I tried to include options for non-baking substitutions in this Instructable. I realize that sometimes you are short on time and need a quick shortcut to finish the @#$% project before 2 am, or maybe you have young children who are making these as gifts for their teachers and you can't have them around hot ovens--don't worry, I got you covered!


Step 1: Selecting Your Container

I like the Ball mason jars (2-cup capacity) for this project the best, but in one instance I had to use a plastic cupcake container in a pinch because the mini gingerbread display wouldn't fit in anything else. The jars should be washed with soap and completely dry before putting your edible display inside.

Step 2: "Charcoal" Layer

Charcoal absorbs unpleasant odors in a traditional terrarium, and helps keep the closed jar environment healthy and free from mold and mildew. Luckily, we have many fun options to choose from to replicate this layer in edible form.

Charcoal Options

Betty Crocker Decadent Supreme Sprinkles, Red Velvet Cake and German Chocolate Cake varieties

Crushed Oreos

Black sprinkles

Chocolate sprinkles/jimmies

Chocolate curls or flakes

I separated my containers of Betty Crocker Decadent Supreme Sprinkles into charcoal-like chunks and placed it as the base layer for a few of the mason jars (I kept the smooth round crumbles for a different layer discussed later in the ible.) For the rest of the edible terrariums, I crushed Oreo cookies into crumbs with a rolling pin and a Ziploc bag and used that in the bottom layer of jars.

Step 3: "Small Pebble" Layer

The purpose of the gravel or pebble layer in a terrarium is to provide drainage and prevent the plant roots from sitting in water and causing rot and death to the plants. We can make our own edible river rocks for our terrarium using model chocolate, Oreo crumbs, food coloring, and cocoa powder.

Candy Clay/Modeling Chocolate

White and green colored candy melts (preferably two different shades of greens, one sage and the other more puce green)

Corn syrup

Plastic wrap

I had two different green colors of candy melts in my cupboard, so I decided to make two different shades of green modeling chocolate (also known as "candy clay" since I am using candy melts instead of actual chocolate). Not pictured, but very much needed for the chocolate pebbles process, is white modeling chocolate, so make sure you whip up a batch of white as well.

For every 4 ounces of candy melts, you will need 1 ounce of corn syrup. I had 12 ounces of both the green candy melts, so I used 3 ounces of corn syrup each to make them into modeling chocolate. I only had 8 ounces of the white candy melts, so I used 2 ounces of the corn syrup.

Heat up the candy melts just to the melting point, or else they will overheat and be unusable if you are not careful. This usually means short bursts in the microwave (30 seconds or less at half power) and lots of stirring to evenly distribute the heat. When completely smooth and melted, pour the corn syrup on top of the melted chocolate. With a slow folding-like and squishing motion, stir the mixture to make sure the corn syrup has come into contact with--and seized--all the chocolate. By stroke number 25, the modeling chocolate is becoming a ball that will not stick to the sides of the bowl anymore. By stroke number 26, you have overworked the modeling chocolate and it is releasing its oils now--stop! STOP!

But seriously, it is a fine line between underworked modeling chocolate, with bits of hard chocolate in the mix that never came in contact with the corn syrup, and overworked modeling chocolate, floating in an oily pool. I like to error on the side of overworked, rather than underworked modeling chocolate, because I can't stand the hard bits of un-seized chocolate floating around in my smooth clay. So when I come to the point of the chocolate releasing its oils when I am stirring it around, I pour off the excess oil down the drain and wrap the remaining candy clay in plastic wrap to rest overnight. In the morning, it will be hard as a rock, but with enough kneading, it transforms into smooth modeling chocolate that is perfect to work with!

Even if your modeling chocolate turns out to contain little bits of chocolate after kneading it in the morning, don't despair! If you are only using the modeling chocolate for rocks and moss, it will still work even if it is a chunky-monkey. Modeling the succulent plant probably won't go so well, however, so you might need to make another batch or use fondant in that case.

Candy River Rocks

White modeling chocolate

Food coloring (gels, candy coloring, or even liquid food dyes all work)

Crushed Oreo crumbs

Cocoa powder

Pinch off 3 to 4 golf-ball sized chunks of white modeling chocolate to color with your choice of food colors. (I used pink, blue, purple, and grabbed a piece of my green modeling chocolate instead of coloring another section green.) Splitting each colored section into two balls, dip them into different colors of cocoa or mix different amounts of Oreo crumbs in it to now get eight differently colored candy clay balls. If you need to add a touch more food color to some sections to make them stand out more, go ahead. Pinching off small amounts of the clay in your fingers, roll it around and form irregular pebble-looking shapes. Let them harden on plastic wrap on top of a cookie sheet. Put the chocolate candy rocks into your mason jars on top of the charcoal bits.

For the non-baker: You can sometimes find candy river rocks in specialty candy cake stores or else purchase it online.

Step 4: "Sphagnum" Layer

Also commonly known as "peat moss", the sphagnum layer in a terrarium can store lots of water, since both living and dead plants can hold up to 20 times it's own weight in water. A toasted layer of coconut mixed with crushed chocolate-covered pretzels seemed like a great substitute for this super-sponge moss.

Toasted Coconut

Cookie sheet

Shredded coconut

Layer coconut on a baking sheet and bake in 350 degree F oven for 10 to 13 minutes. Check after 10 minutes and every minute after for doneness--it can change in a blink of an eye from yummy toasted coconut to nasty burnt coconut.

I crushed a bag of chocolate-covered pretzels using a rolling pin and a Ziploc bag. I mixed the coconut and pretzel crumbs together and spooned it into the mason jars on top of the candy pebble layer. Make a shallow well in the layer in preparation for the next step.

For the non-baker: You can leave out the toasted coconut and just use the crushed-up pretzels as your sphagnum layer.

Step 5: "Mud" Layer

Between the lower layer of sphagnum (which holds large quantities of water), and the potting soil above, it makes sense that a layer of mud must lay where the two intersect. Or maybe I just needed a layer of frosting for the palatability of this dessert, and next to the chocolate cake seemed like the best place. We'll never know. . .

Whipped Chocolate Ganache Frosting

6 ounces milk chocolate

4 ounces heavy cream

1 Tablespoon unsalted butter

Put the chocolate pieces in a metal or glass bowl. Heat the heavy cream to the boiling point in a saucepan on the stove. Pour the heavy cream over the chocolate and wiggle the bowl to make sure all of the chocolate is covered. Cover the bowl with a plate or lid and let stand for 10 minutes. Whisk the chocolate until it is dark and shiny and then let it completely cool to room temperature (it will turn less shiny and become more matte when it is ready). Place the chocolate ganache in a bowl with a tablespoon of softened butter and blend with a hand mixer until light brown and fluffy in appearance.

Scoop the chocolate frosting into a piping bag, or a Ziploc bag with the corner snipped off, for mess-free placing into the jars. I squirted the chocolate frosting into a shallow well I created in the coconut/pretzel layer so it wouldn't be seen from the outside of the mason jar.

For the non-baker: You can substitute chocolate frosting in a can you find at the store.

Step 6: "Potting Soil" Layer

Some common ingredients used in potting soil are peat, composted bark, sand, perlite and recycled mushroom compost, and in our terrarium, it is replaced with tasty chocolate cake and crispy white chocolate pearls.

Chocolate Cake

2 sticks (1 cup) unsalted butter, softened

14 ounces (2 cups) granulated sugar

12 ounces (2 2/3 cups) of all-purpose flour

1 teaspoon salt

1 teaspoon baking soda

2 teaspoon baking powder

4 ounces (1 1/3 cup) unsweetened cocoa powder

8 ounces (1 cup) sour cream

1 teaspoon vanilla extract

1 teaspoon almond extract

2 eggs, room temperature

1 1/4 cups strong coffee

It helps to have all your ingredients sifted and whisked together and set aside before you start making the cake.

Sift and whisk the flour, cocoa powder, baking soda, salt, baking powder together in a bowl. Set aside. Mix the vanilla and almond extracts in with the sour cream (I mixed mine right in the container, as I only had one cup of sour cream left in it), set aside. Crack your room temperature eggs into a separate bowl and set aside. Brew the coffee and set aside. Preheat the oven to 350 degrees F. Grease your cake pan, line the bottom with parchment paper, and grease and flour your pan. I used a 11 X 15 X 2 pan for this recipe. This is a lot of cake--way more than you need for a couple of mason jar terrariums! You can half the recipe and bake it in a smaller pan if you want. I went ahead and made a full recipe because I figured my family wouldn't have a problem with extra cake around to eat. I wasn't disappointed.

If your butter sticks aren't softened in time, an old trick is to bang it with a rolling pin. One or two whacks and the butter is ready for creaming. Blend butter and sugar together until light, fluffy, and smooth, usually a good 5 minutes depending on the human with the hand mixer, or less if you have a stand mixer.

Mix in the eggs one at a time on low speed. Add 1/3 of the flour, mix in, add 1/2 of the sour cream mixture, mix in, add another 1/3 of the flour, mix in, add the last 1/2 of the sour cream mixture, mix in, and finally add the last 1/3 of the flour, mix in.

Slowly mix in the coffee on low speed until mostly incorporated. Scrape down the sides of the bowl and beat with a mixer at medium speed until thoroughly combined. Smooth and level the batter into the cake pan and bake around 30 minutes (check the oven when you start to smell a strong chocolate cake flavor in the house, it means it is getting close to being ready). The cake is done when you can lightly press the middle of the cake with your fingers and the cake returns to its previous shape instead of leaving sunken fingerprints.

Let the cake cool in the pan 20 minutes. Run a knife around the edges of the pan before flipping the cake over out onto a sheet pan or piece of food-grade cardboard. Peel away the parchment paper, if used, and wrap the chocolate cake in plastic wrap until needed.

When ready, break up chunks of the cake into a large bowl and use a fork to reduce it large cake crumbs. Add a tablespoon or two of the white chocolate pearls or leftover round cookie sprinkles from the German Chocolate Cake Betty Crocker Decadent Supreme Sprinkles container (see, I told you we would use it later). Your potting soil is now ready to place into you mason jars.

For the non-baker: You can purchase an already-made chocolate sheet cake or cupcakes at the grocery store.

Step 7: "Green Moss" Layer

Plants and mosses are what make a terrarium, well um, a terrarium. Otherwise, it would just be a jar with dirt and rocks in it. Our edible plants, made from modeling chocolate/candy clay, also give our jar personality and authenticity of looking like an actual terrarium.

Take a small chunk of kneaded green modeling chocolate and push it through the back of a fine mesh sieve, like the one commonly used to sift dry ingredients together in a recipe. The modeling chocolate should press up through the tiny holes in the sieve and look like small clumps of moss or grass coming out of the front. Scrape off a section or two with a knife and place them in your jars. And if you are feeling especially bold, you can try pressing one color through a little bit, and then switch to a different color behind it and come out with two-toned/ombre-colored moss or plant. The longer you press the modeling chocolate through, the longer the moss will be--until it looks more like long grasses instead of moss. It is up to you how long or how short you want your plants, you are in control of your artistic urges!

For the non-baker: You can substitute commercial fondant (pre-colored green even) to use instead of modeling chocolate for the moss. You can also purchase green frosting in a bag and the "fur/grass" tip to go on top and pipe out strings of frosting to represent grasses in your terrarium.

Step 8: "Fun Landscaping Accessories/figures" Layer

Traditional terrariums turn into whimsical landscapes using rocks, toys, figurines, plastic animals and other treasures. This is even more true for our edible version by using sugar figures, cookies, and edible snow glitter.

Royal icing accessories, sugar-paste flowers--whatever you can find at the store in the baking aisle is fair game for your terrarium. You can even make small gingerbread cookies and mini gingerbread houses to display in your edible mason jars. I had white edible glitter on hand to replicate snow in some of my terrariums. If you can't find edible white glitter at the store, you can make it using the following recipe:

Edible Snow Glitter

1 tablespoon (1 packet) of unflavored gelatin, like Knox

3 tablespoons cold water

Pearl sheen cake airbrush color

White liquid food color

Acetate sheet or smooth flexible cutting board plastic (not parchment paper or wax paper--these do not work!)

Evenly sprinkle the packet of gelatin over the cold water in a microwaveable safe bowl. Do not mix it yet. Use a squirt bottle to sparingly spray any sections that have not become damp. Heat in microwave for 30 seconds, 10 seconds at a time so it doesn't boil. Skim off the white cloudy surface layer, and squirt in a small amount of the pearl sheen color, and a drop or two of the white color if you would like it a little more opaque. Now you can mix the gelatin and color together and spread it out onto a sheet of acetate to dry for 6 to 8 hours, or until it starts to peel up at the corners. Cut the gelatin sheet into smaller sections and grind it in a blender or spice/coffee grinder until it is as fine or coarse as you want. Voila! You have just made edible glitter for your winter scene terrarium.

For the non-baker: You can buy small gingerbread man at the store and cover them in Wilton white cookie icing for a homemade look and feel to your cookies.

Step 9: Bonus "Succulent Plant" Level

Succulent plants are great for open-top terrariums, because they don't thrive in the moist ecosystem that the closed-top terrariums provide. Succulents prefer drier conditions of the open air and bright, indirect sunlight. Our succulent isn't so picky about its environment, because it is made out of modeling chocolate or fondant.

Succulent Plant

Light green modeling chocolate or fondant

Leaf shape cookie cutters in small, medium and large sizes

Petal dusts in sage and violet

Small paint brush

Large round brush

Light green candy melts to use as "glue"

Small rolling pin

Paper towel

Powdered sugar

Using the modeling chocolate we made earlier that is the closest shade to your ideal succulent plant model, dust your surface with powdered sugar to keep the modeling chocolate from sticking to the table/roller. Roll out a section of modeling chocolate, and use the small, medium, and large-shaped leaf cookie cutters. You will need around eight of each petal size if you want to follow along with my model pictures. And as always, make extra leaves in case of breakage, mishaps, etc.

if you can not find anything that closely resembles the leaves of your succulent plant in a cookie cutter shape, you can make your own by pressing and deforming a cheap circle cookie cutter into the shape you need.

If at any point your modeling chocolate is getting too warm or sticky or droopy from being handled, step away from the chocolate to let it rest, or put it in the fridge for a few minutes to firm up. The modeling chocolate needs to be stiff and dry to hold its shape, so plan for a little downtime in between leaf sections to let it harden up again.

Give the leaves a little concave flow to them by lifting up the ends. Brush the violet petal dust on the tip (both sides) of the leaf using the small paint brush. Then apply the sage petal dust all over and to both sides of the leaf using the large round brush. Try blotting the paint brushes on the paper towel for more control over your petal dusts and coloring.

Melt a few candy wafers the same color as your plant (or as close as you can) in a small bowl and set it over a cup of hot water to keep them melted while you work. Using a clean small paint brush, attach the petals to each other in a spiral pattern, starting from smallest leaves, cut in half, and then onto the whole small leaves. Then attach layers of the medium leaves under the small core of small leaves. Lastly, move onto the largest-sized leaves and layer them under the medium leaves of the succulent. Use a picture of a real succulent or follow along with my pictures as a guide.

When you are happy with the look of your plant, gently place it on top of the potting soil layer in your edible terrarium. Stand back and admire your hard work.

For the non-baker: I got nothing for you to substitute making this plant by hand. You should stick with the moss and icing figures.

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    26 Discussions


    Reply 4 years ago on Introduction

    Thank you! I hope to be half as good at writing instructables/winning contests as you are--you have fantastic projects!


    4 years ago

    Have you considered making separate instructables for some of the techniques used in this project? The edible snow glitter and making and using the modeling chocolate, especially. You do such a fantastic job explaining and demonstrating them, I'm sure we would all appreciate learning from you.

    Either way, I wish I could give you more than one vote in each of the contests! This really blows the competition away.

    3 replies

    It is kinda long, isn't it? I should break it up into separate instructables, like you said. I was just in a hurry to get it up because of the holidays, and in case somebody wanted to try it in time. I love looking at the other instructables for my diy gift giving, and I love that people have such great ideas they are willing to share here--I hope I can be like that for someone else. Thank you for your votes, I do appreciate it very much!


    Reply 4 years ago

    I don't think this one is too long, especially given how complex it is. I was more thinking for ease of finding the techniques when people are searching the site. If someone's looking for help on modeling chocolate, they might not think to look in the middle of a larger project?

    Ah, I understand the reasoning now. Yes, that makes sense. I can make a separate modeling chocolate instructable when I make another batch, that way I can get better pictures of the coming together process. Thanks for suggesting it!


    4 years ago

    I am absolutely in awe. I started reading this wondering how the heck it could be safe to put an actual plant on top of cake... I grow that particular succulent and still mistook it for the real thing! Not only are these lovely and realistic, the attention to the little details most people forget is seriously impressive. I've never seen a project that added "perlite" and "peat moss" to their "dirt", but that definitely takes it from cute to incredible. Bravo! I envy those teachers.

    1 reply

    Your comment made my day! I was hoping my succulent was realistic enough that somebody would do a double take. Thank you for saying such nice things about my 'ible, it really makes documenting the little things worth it! I tend to go over the top with my cakes, and sometimes I wish I could channel the "less is more" mantra because I love the beautiful simple desserts people post.


    4 years ago on Introduction

    So wonderful! I wonder how many teachers just put them on their desk because they thought they were real.

    1 reply

    Reply 4 years ago on Introduction

    Ha! I never took a picture of what the final packaging looked like because I was busy finishing them up in the parking lot of the school before the bell rang for the end of class. I stuck a label on the top which read "Completely edible terrarium" and wrapped a wooden spoon around the jar with red and white baker's twine. When my kids delivered them, they made sure to tell their teachers that they were fake and meant to be eaten.


    4 years ago on Introduction

    They look so real. Great work and great idea ...I am super impressed Very creative.. I make lot of terrarium for once I thought this was real till i read the instructions

    1 reply

    Reply 4 years ago on Introduction

    Thank you for your compliments. I don't think I can take credit for the idea of an "edible terrarium", since other people have come up with edible terrariums before. But I did think up of my plan and my processes entirely on my own. I thought it would be fun to document because I was able to turn something that was frustrating (not getting real terrariums in on time) into a positive fun gift for the teachers. I have to whip out my cake tools every once in a while to keep from getting rusty at it!


    4 years ago on Introduction

    These look so cool! They look more involved than what I would call "last minute" gifts, but definitely something special I'd make for my plant fanatics. The sieve-made moss is awesome!

    1 reply

    Reply 4 years ago on Introduction

    I know, "last-minute" is a relative term with me because I don't like to procrastinate on projects that I wanted done, like, last month! I used to decorate cakes in a former life (just as a hobby) and I still have a obsession with collecting lots of sprinkles and fun cake decorating tools, especially around the holidays. I have to do a purge session every once and a while to get rid of edible supplies which might be getting old in my cupboards. This seemed like a good project for that. That sieve has done a lot of moss/bushes in its lifetime when I used to decorate cakes. It finally broke after this project, so I bought myself a new one.