Introduction: Advanced Truffle-Making: Slabbed Ganache and Multi-Layer Truffles
There are few things I enjoy more than crafting chocolate truffles at home. they make great gifts, it makes your kitchen smell like chocolate, and nobody can ever believe that they're home-made.
There are many excellent chocolate-based confectionery procedures here on Instructables. I particularly like simplicity and ease of Scoochmaroo's Easy Truffles, the ever-updating recipes in Ian's Anatomy of a Chocolate Truffle, the artistic humor of Mousewrites' Dung Beetles, and Raving Mad Studios' Velveeta Cheese Fudge, because it's fudge with velveeta in it.
The two drawbacks of hand-rolled truffles are that you have to hand roll the centers (which can take a while and be messy), and that it's difficult to produce multi-flavored and multi-textured candies. So, if you wanted to make a peanut butter and jelly truffle that had separate layers of peanut butter and jelly, it would be quite challenging, if not impossible.
The solution to this is to produce the truffle fillings in slabbed form. Slabbed ganache is exactly what it sounds like - ganache, set into a slab. It's an easy way to make truffles that contain multiple types and flavors of filling together to produce a most interesting chocolate-consuming experience. In this instructable, I'll be showing you how to make kona coffee/marshmallow truffles, but the procedure can be used for all sorts of fillings.
The drawback to slabbed ganache is that it calls for some additional equipment, which will be covered in step 2.
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Step 1: Background Reading
I learned how to do this (and more) from Peter Greweling's unmatchable book Chocolates and Confections: Formula, Theory, and Technique for the Artisan Confectioner. The method I use to make marshmallows and to temper chocolate are both from this book.
If you're starting out and want a less pricey introduction to chocolate-making, Andrew Shotts' book Making Artisan Chocolates has a fantastic selection of recipes and a nice, straightforward introduction to tempering. If you want a book that has a good number of recipes for truffles and also an explosion of other chocolate desserts (and dinners!), Jan Hedh's appropriately-titled Chocolate will not disappoint, and is only $2-3 for a used copy.
Step 2: Required Equipment
- A kitchen scale, with a resolution of 1 gram.
I can't say enough good things about cooking by weight. Once you get even a little experience with a scale, you'll be amazed at how fast everything gets. Fast... and accurate!
- An instant-read digital thermometer
Temperature control is critical in candy-making. You'll need a fast-reading digital thermometer for making the marshmallow, the ganache, and tempering the chocolate. I have this thermometer, which I like quite a bit.
- Two 12x12x¼ inch confectionary frames
Confectionary frames can be anything that keeps poured liquid or semiliquid centers confined and shaped. Also suitable are caramel rulers, heavy metal bars that are cheap and resizeable.
I had my confectionary frame (which I use in this instructable) laser-cut from acrylic by Ponoko because I like the stability a one-piece frame offers. (Read: I'm too much of a bonehead to keep from knocking caramel rulers around)
... and because I have always wanted to use Ponoko. Laser cutters are awesome.
- A stand mixer with a balloon whisk attachment
This is for the marshmallows. If you're using a hand mixer, make sure to use a durable, stainless steel bowl. Sugar syrup is hard enough to clean up, and you don't want to add molten plastic into the mix.
- A very long offset spatula, a ruler, or something else that can smooth down surfaces.
After pouring the fillings into the frame, they'll need to be smoothed out. A heavy 18 inch metal ruler works perfectly for this. I've lost my ruler, so I had to use an offset spatula.
Forewarning: I lack skill with an offset spatula. You'll see.
- Parchment paper
Parchment paper, like laser cutting, is awesome. It's the perfect surface to spread confections on, as it imparts no flavor to the mixture and is non-adhering.
It has a million other uses, too. You can use it to store cookie dough, to bake cookies on, or even to cook delicious fish inside.
Step 3: Ingredient List
For the marshmallows, you will need:
Unflavored Gelatin (15 grams)
This gives the marshmallow its desirable properties by trapping the air that will be whipped into the sugar syrup. Of course, this means that strict vegetarians (and vegans) will be unable to enjoy your treats! If you'd like to try making a vegan marshmallow instead, instructables user Randofo has your back.
I have no idea if vegan marshmallows are compatible with trufflemaking. If anyone happens to try it, please leave me a comment!
Water (60 + 80 grams)
Vanilla extract (10 grams)
Vanilla has the power to enhance the other flavors in the marshmallow.
Sugar (240 grams)
Corn syrup (140 grams)
Glucose syrup (combined with invert sugar) is what you should be using, in an ideal world. For those who live in an area where it is difficult (if not impossible) to find pure glucose syrup in grocery stores, corn syrup is an acceptable substitute.
Honey (40 grams)
Honey adds both sweetness and flavor to the marshmallows. Don't skimp on the honey! I used wildflower honey for this batch.
Agave nectar (20 grams)
This ingredient is optional, but I like the flavor. If you omit the agave nectar, add an extra 20 grams of corn syrup.
Nutmeg (1 tsp)
Other spices can be substituted for nutmeg. It is difficult to know how intense the flavoring will be at the end of the process, so be cautious with it. I have made this recipe with 1 tsp of both nutmeg and cinnamon, and found the resulting flavor (in the marshmallow by itself) ideal for my taste buds. In this particular truffle, 1 tsp of spice is overwhelmed by the coffee flavoring in the ganache. Your mileage may vary.
For the ganache, you shall require:
Heavy cream (206 grams)
Use high-quality heavy cream. I use Organic Valley heavy cram if I can get it, because it is thick and delicious.
Bittersweet chocolate (396 grams, tempered + extra for dipping)
Make sure you get a good quality chocolate of at least 60% cacao content. Most professional recipes recommend Valrhona or Callebaut, but I use Ghirardelli. The price is right, and I can buy it in local stores.
You might want to shop around for the chocolate. In my area, there is a shocking price difference between stores: for a 326 gram (11.5 oz) bag, prices here range from $2.50 to $6.50.
Commercial chocolate is always pre-tempered.
Honey (63 grams)
Unsalted Butter, softened (55 grams)
Don't forget to take your butter out of the fridge in advance! Slabbed ganache requires softened butter, so that the chocolate in the ganache remains tempered and workable. Using cold butter will drop the temperature of the ganache too fast.
Coffee (10 grams)
You can either use whole coffee beans cracked in a mortar and pestle, or ground coffee. I'm using Kona coffee (ground) for my batch.
Got everything together? Let's make some truffles!
Step 4: Marshmallow Layer: Hydrate the Gelatin
You want to have everything ready to go before you start preparing the marshmallows.
Prepare your first set of confectionary frames. Oil the parchment paper well, or your marshmallow will stick and you will be sad.
Attach the balloon whisk to your stand mixer.
Weigh out 15 grams (about one and a third packets) of powdered unflavored gelatin. Mix this into 80 grams of water in a microwave-safe cup, and set it aside to let it hydrate. Don't worry about timing it, it'll be fully hydrated by the time the sugar syrup is cooked.
Step 5: Marshmallow Layer: Cook the Syrup
Into a saucepan, measure out:
240 grams sugar
140 grams glucose (corn) syrup
40 grams honey
20 grams agave nectar
60 grams water
1 tsp ground nutmeg
A quick note: In the pictures below, I've laid out all of the ingredients separately. When you prepare these marshmallows for yourself, it is much easier and more accurate to measure them all directly into the bowl.
Weigh out 10 grams of vanilla extract, and set aside.
Mix everything but the vanilla together, and heat it over medium-high heat on the stove. Your goal temperature is 252 °F (122 °C). Stir the mixture occasionally to ensure uniform distribution of all the ingredients.
When the target temperature is reached, pour the syrup into the bowl of the stand mixer and allow to cool (WITHOUT whipping) to 212 °F (100 °C).
Step 6: Marshmallow Layer: Whip It Up!
While the syrup is cooling, put the hydrated gelatin into the microwave to melt it. Keep an eye on this! You don't want it to foam over.
A second or two of boiling will leave you with a clear solution.
Add the gelatin solution to the 212 °F sugar syrup, and begin whipping at high speed. As the mixture is whipped, it will begin to turn from a saucy tan to a lighter pasty white color. Whip it for about 4-8 minutes.
Remember that vanilla extract you weighed out before? Add it in at the end of the whipping time. Make sure it's mixed in thoroughly.
Once the whipping is complete, pour the marshmallow into the prepared frame. Level and smooth it, then cover with a well-oiled piece of parchment paper. The marshmallow must be allowed to cool fully before you begin to prepare the ganache. In my 63-degree (F) kitchen, this took about three hours. I gave it an extra hour to be safe.
This would be a good time to clean the kitchen. If you got marshmallow or sugar syrup on something, 10-15 minutes soaking in hot water will dissolve it right off.
Step 7: Ganache Layer: Prepare the Cream
Now, it's time to move on to the ganache.
First, prepare the second frame. Peel the parchment paper (carefully!) off of the top layer of the marshmallow, and set the top frame in place. Now you're ready to go!
To start out, make sure you have two microwave-safe containers and a mesh strainer on hand.
Weigh out 20 grams of heavy cream into a microwave-safe container. Mix 10 grams of coffee into the heavy cream, bring to a boil in the microwave, and allow to steep for 5-7 minutes.
Into the other container, weigh the 63 grams of honey. Tare (zero) the scale with this container still on it.
Filter the coffee/cream mixture into the honey container using the strainer. The weight of cream will have decreased; add additional cream to bring it back up to 206 grams.
Bring the coffee-honey-cream mixture to a boil in the microwave; stir until uniform. Allow the mixture to cool - the target temperature of the cream component is 104 °F (40 °C).
Step 8: Ganache Layer: Mix It Up!
Make sure you have everything on hand; your soft butter, the coffee-honey-cream mixture, the thermometer, and your prepared frame.
The key to tempering chocolate is to proceed with caution. I like doing this in the microwave, because it is easy to finely control the amount of heating the batch of chocolate gets.
The method used here is known as "incomplete melting." The goal is to carefully melt out the unstable cocoa butter crystals, seed the remaining batch with a small amount of reserved chocolate.
Weigh out the 396 grams of chocolate. Remove about 20% of it (~80 grams), chop it into smaller pieces with a knife, and set it aside.
Use short (10-20 second) bursts of microwaves to heat the chocolate. Between each period of irradiation, stir the chocolate around to make sure there are no hot spots forming. Do not let the temperature of the chocolate rise above 97 °F (36 °C).
If the temperature of the chocolate rises above 97 °F, it will lose its temper. Angry chocolate is bad chocolate.
Once the main batch is uniformly melted, mix in the chopped "seed" chocolate. It should melt in, seed the batch with the proper form of cocoa butter crystals, and bring the whole lot down to the proper working temperature. You can test the chocolate by smearing a bit on a piece of aluminum foil - it should set quickly, and without white streaks.
Massage the butter into the chocolate, until no lumps remain. Pour the 105 °F cream over the mixture (heat it up if it's cooled too much), and stir in a figure-eight motion until you get a smooth, uniform ganache.
Pour the ganache into the frame and smooth the surface. Allow it to cool a bit, cover with parchment paper, and leave to crystallize overnight.
Step 9: Finishing the Truffles: Precoating and Cutting
Before the slab is removed from the frame, the ganache layer needs to be precoated (or "bottomed") with a thin layer of tempered chocolate. This keeps the ganache from sticking to the dipping fork, which makes it much easier to dip.
To precoat the bottom, melt and temper a small amount of dark chocolate. Pour it onto the slab, and spread it with the offset spatula (or ruler). Be quick! It will crystallize very fast. Let it rest for an hour or two, then you're ready for cutting.
A professional chocolatier would probably have a guitar to cut the slab with, which would make the process fast and easy. In the absence of a guitar, I'd imagine that some sort of MacGyvered contraption with piano wire would work.
In the absence of piano wire and MacGyver, a lightly oiled knife is an acceptable substitute. I bet a pizza cutter would work well, but I have never tried that.
Remove the slab from the frame by working a thin metal object (like your offset spatula) around the sides. The frame should be able to be lifted cleanly off. Flip the slab over (carefully!) so that the marshmallow layer is up.
Cut the slab into pieces with the knife. You can make them as big or as small as you want! I made some big ones for people I really like, and some small ones for people I really like that are on diets.
Some caveats: The knife will need to be cleaned and re-oiled regularly, so that adhesion doesn't ruin your day. This is especially a problem with a marshmallow layer. Also, the knife will crack the precoat layer on the bottom as you cut. Without using a wire cutter, this is inevitable. When you coat the pieces in the last step, the extra chocolate will hide this.
Don't worry, you can always eat centers that turn out looking funny.
Step 10: Finishing the Truffles: Dipping
After all that, the final step is somewhat anticlimactic.
Temper some chocolate.
Dip the centers.
If additional finishing is desirable (say, if you wanted to press a coffee bean into the top), do it before the chocolate sets.
Leave them alone for 24 hours.
It's important to not disturb the dipped and finished chocolate for a while, so that the cocoa butter is allowed to crystallize fully. Touching or moving the chocolates will almost always result in unsightly defects.
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