Introduction: Cupcake Fault Line Cake StewieWorks

July is Birthday month at StewieWorks. To celebrate I jumped on the trendy band wagon and made one of those fancy Fault Line cakes, but because I'm me and it can't just be the basic... it's gotta be extra! I did my homework and couldn't find a cake that was made with 9" cake rounds, 4 tiers (at that cake size), with mini cupcakes, and be able to slice through the whole cake without pulling pieces apart. (yikes that was a sentence to write!) Few ups and downs with homemade buttercream and finding the gold to go around the fault. The basics of a fault line cake is that whatever you fill around the middle of the cake in the "Fault" does not stick farther out then the rest of the cake. This is so it looks like it's inside the cake. Overall, for a first try I think it turned out pretty good. Why did I do chocolate and vanilla cake - I'm not really sure? :-P


(2 or 4) 9" cake pans

mini cupcake tin

mini cupcake wrappers

offset cake spatula

long flat cake spatula

tray to serve cake on

lazy susan (cake stand to decorate on)

parchment paper

cooking spray



pipe bag

pipe tips (I used whatever I had at the time, you can use what you like)


(2) Butter vanilla cake mix (yeah I was lazy for this and didn't home make the cake mix, but that's cause box cake isn't soft and fluffy and is easier to work with building wise)

(1) Chocolate cake mix

Whatever ingredients you need for your box cake mix. I think butter, eggs, water, oil....

Big Bowl to cake in mix in

frosting mixing bowls

Measure cups/spoons

Mixing spoons

Stand Mixer

Powered Sugar

Cocoa powder

milk (anything other than skim)

Vanilla Extract

Butter (lots!)

food coloring



gold pearl candies (gold luster dust is what you are supposed to use, but I couldn't find any)

Refrigerator (cool cake is easier to work with)

Step 1: Bake Your Cake

Follow the directions on the box mix, and prep your cakes. Before you go ahead and pour the batter into the pans, let me share a secret (that probably isn't a secret, but is the first time I've done this so ramble ramble ramble, I shared.) Put your cake pan onto laid out parchment paper. Trace a circle around the bottom. Cut out the circle (don't leave any pencil marks, not tasty.) Spray the sides with nonstick spray. Place the parchment circle in the bottom of the pan. Now pour in your cake batter. For the mini cupcakes go ahead and use the vanilla butter mix and cupcake wrappers.

Make two 9" vanilla butter cakes, two 9" chocolate cakes, and 12-24 mini vanilla butter cupcakes.

Bake according to the box directions.

Step 2: While They Bake Make a Powered Sugar Mess.

I'm not kidding. I hate making homemade buttercream frosting. It's not that it's not tasty, its just such a mess! I made five batches of frosting for this cake. Three vanilla, and two chocolate. I don't really have a recipe per say... lol. It's two parts powered sugar to one part butter. Mix and see how stiff it its. Add a tablespoon of milk at a time to thin it to the correct consistency. (usually like 2 does the trick). If adding in something like vanilla, subtract some of the milk or if adding cocoa powder to make chocolate subtract some of the powered sugar. (for my double batch of chocolate I used to tablespoons worth of cocoa powered).

For this cake, I made a double batch of chocolate. Then made a SINGLE batch of vanilla with vanilla extract. Then made another batch of vanilla without the vanilla extract, just powered sugar, butter, and milk. Then added a few drops of purple food coloring. Did the same again and added green food coloring.

A helpful tip, keep the butter and milk cold. This will take a little longer in the mixer, but with make a stiffer frosting that will be easier to work with in a piping bag.

The messy part - you use a stand mixer or mixer (or even spoon). The amount of sugar to liquid no matter how hard you try poofs out of the bowl. lol. I have the plastic cover for my stand mixer and put a kitchen towel over the whole thing, and still poofed up and out. (if anyone has any tips and tricks PLEASE LET ME KNOW! lol)

Anyways, mix till it gets to a consistency you are happy with and scoop into separate bowls.

Step 3: Cool Cakes (they Don't Just Wear Sunglasses)

pull cakes from the oven and let them cool. Not kidding. I normally can't wait and start frosting wayyyyy to early. Let them get room temperature. When you turn out the cakes, remember the parchment paper at the bottom. This is so the cake pops out of the cake pans easier - and yes it works. I didn't get the middle chunk out like I usually do, however, the cake had to be cooled. I know, I'm late to that party, but I can't believe it actually worked. lol. Pull the cupcakes from the pan and remove the cupcake papers. We baked them in those papers so it was easier to remove from the pans, and we got those little indents in the cupcakes for presentation. (kinda lol).

I always chill whatever I'm not working on in the fridge.

Step 4: Layer 1 & 2

Layer 1:

As per usual, I needed to travel with this cake, so I took one of my plastic cake /cookie trays (this one is round) and used that to stack my cakes. I had chilled these in the fridge, so I didn't need to put a bit of frosting on the cake tray to keep it from moving. level the cake. Don't take off too much from the top, just remove that dome that you get from baking them. Put down a Vanilla cake first. Frosted the middle with the Vanilla buttercream with extra vanilla extract. Chilled.

Layer 2:

This is a chocolate cake. I trimmed the sides just a bit, probably around 1/2 in, all the way around. This made it so that we could put the cupcakes on the sides as decor without them sticking too much farther out than the rest of the cake. I used the vanilla buttercream with extra vanilla again to fill the middle and chilled.

***another trick that you probably already know.... cut strips of parchment paper and tuck them under the first layer. Leave extra parchment hanging out over the sides of your tray. When you go to clean up your finished cake, this will help remove the crumbs and any wayward frosting from your tray without any mess. It will also help you get a clean line around the bottom of your cake.

Step 5: Layer 3 & Mini Cupcakes

Layer 3:

This is another chocolate layer. I carved this one down to match the layer underneath. You can carve these on stacked on the cake, but it makes it easier to clean up if it is done before the cake is moved. I frosted the middle with the vanilla buttercream with extra vanilla extract. I then did a crumb coat with the chocolate frosting.... That's correct. I did a crumb coat without adding the top layer. I then let this chill in the fridge for a few.

Mini Cupcakes:

These I cut in half from the top to the bottom. That way when placed on the side of the cake it looks like the whole cupcake is inside the cake, but the trick is that only half is there. Once those were cut, I pulled the cake back out. I used the chocolate buttercream as kind of a glue to hold the mini cupcakes in place along the side the of the cake. I placed the cupcakes in no particular pattern around the middle of the cake, making sure that some were up towards the top of the chocolate layers, some were in the middle, and others were towards the bottom of the chocolate layers - not going outside of the chocolate layers. I had plenty of left over mini cupcakes fyi. Depending on the temperature in your kitchen you might need to chill the cake to keep the mini cupcakes for sliding. I filled two piping bags, one with purple buttercream, and the other with the green buttercream. I used a medium size round tip for each. Then frosted the tops of the mini cupcakes that were on the side of the cake, like you would normally. I'm not great with a piping bag to start with, so this turned out like it did. lmao. (and I just realized I might have spelled piping wrong somewhere in this tutorial... it's only two p's, and not three.) Chill again. If you want to add sprinkles or candies to your cupcakes, now is the time, it will get harder to decorate these with the top layer of cake on.

Step 6: Last Layer

Layer 4:

pull cake and put the last vanilla layer on the top of the cake. It should hang over the chocolate layers, but not need to be supported. Try and get that layer on the cake stack as centered as possible. Then crumb coat that layer with chocolate frosting. Chill.

Pull the cake from the fridge... now you have it crumb coated and all the cupcakes on the sides. it's time to frost the whole cake. I used the last of the chocolate frosting. This frosting is to go from the bottom to the middle then from the middle to the top, sounds like a duh, right? What you want to do is skip the very middle where the cupcakes are and have them peak through the frosting. Frost around the bottom and then towards the middle. Have the frosting cover a bit of the bottom of the cupcakes and maybe a little bit more in some spots, other spots have the cupcakes completely uncovered. This is to look like the ground has split and the cupcakes are peaking through. Do the same for the top half of the cake. Once you are happy take a long spatula and spread the frosting around the whole cake. Try and get it as even and flat as possible. Don't push any frosting in towards the cupcakes, let that rest/fall as it does. The whole point is not to cover the cupcakes, but have them peak out from the fault line. You get this curvy unfinished edge around the top and bottom of the cupcakes, with a mostly smooth frosting around the rest of the cake.

Gold line - most people I've seen use gold luster dust mixed with water to make a paint to color around that fault edge. I couldn't find anything close to that without ordering it online. I got a mix of gold pearls and gold sugar sprinkles. I put the gold pearls around the fault line top and bottom. They didn't show up as brightly as the gold line usually does, but it worked for me.

Step 7: Decorations

I had enough leftover mini cupcakes that I decided to use some on the top of the cake for decoration. I took a mini cupcake and cut through the bottom stump on an angle. When placed on top of the cake it looks like it's rising out of the top of the cake and the angle cut makes it fun to view. (I dunno it looked pretty lol) I used the chocolate buttercream as a glue under the cupcake onto the top cake. Make sure you don't use too much, you don't want any coming out from underneath. I used five total mini cupcakes on top, four around the edges and one in the center. I took the last of the frosting in the piping bags from when we frosted the mini cupcakes earlier and frosted purple and green on top each of the mini cupcakes (how many times have I said mini cupcakes throughout this tutorial - sheesh!) I then made a new pipe bag with chocolate frosting and used a smaller star tip to make pretty little star/flowers along the bottoms of each cupcake - where the cupcake met the cake. I added sprinkles to match the cupcakes in the middle of the cake and then added some more of those gold pearls in the stars at the bottom of the cupcakes.

Pull the parchment paper from the bottom slowly! the weight of all the layers makes it harder to slide these out, so just go slowly. You can re-adjust your frosting if needed at the bottom with your spatula. I added some more of those candies that I put on the cupcakes around the bottom of the cake. I dumped them onto the tray around the bottom and took my spatula and pressed them up onto the sides of the cake, keeping them all at the bottom. So some where on the cake tray and others were on the cake bottom/side.

I chilled the cake in the fridge until I left to go deliver it. I did that because it's about 100 degrees here in July and I was getting into a hot car early afternoon soooo yeah.

I made a video over on youtube as well, if you'd like to see it.

My travels kinda spilled all the loose bits of candy onto the floor of my car - oops.

Hope this was useful! Let me know if you make a fault line cake, share a picture too! We'd love to see it. Enjoy!