Step 1

Preheat the oven to 350 degrees F.

Step 2

Remove the paper from the outside of your empty cans and clean them well. Grease and flour the inside of the cans. Set aside.

Step 3

In a large bowl, combine sugar, flour, unsweetened cocoa, dark cocoa, baking soda, and baking powder. Whisk the dry ingredients until they are well distributed.

Step 4

Add the eggs, coffee, buttermilk, oil, and vanilla to the dry mixture. Using an electric mixer, beat for 2-3 minutes, or until there are no lumps. The batter will be quite thin compared to typical cake batter.

Step 5

Pour the batter into the cans, filling each about half-way.

Step 6

Bake for about 25-30 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Step 7

As you wait for the cakes to bake, make the Peanut Butter Frosting. Using an electric mixer, beat the butter and peanut butter together in a medium sized bowl.

Step 8

After the butter and peanut butter are well combined, slowly add the powdered sugar as you continue to beat together the ingredients. Then, add the milk, and beat until the frosting reaches your desired consistency.

Step 9

When cakes have finished baking, be sure to let them cool completely. You may then either remove them by popping them out of the can, or if you are having difficulty, use a can opener to open the other side of the can and then push them out. Either way, be careful of sharp edges!

Step 10

After you have removed the cakes, you will notice that the top of the cake tower is rounded, like a cupcake or muffin top. Carefully and evenly cut this part off, so you are left with an even cylindrical cake. Then, cut the cake into equal layers. I cut mine into 4 layers. Try to cut them evenly, as uneven layers may cause your cake to tilt.

Step 11

To frost in between the layers, pipe frosting around the edge of the top of one layer. Then, pipe another, smaller circle inside of that one. Using a knife, even out all of the frosting to get a smooth layer. You can simply slap on the frosting using a knife instead, if you’d like, but you will likely wind up with a much messier looking cake, as I found out the hard way.

Step 12

After you have topped each layer with frosting, re-stack them to assemble your layer cake. Place the tower cakes in the refrigerator as you make the ganache.

Step 13

To make the ganache, start by putting the dark chocolate chips into a large, heat-proof mixing bowl.

Step 14

Heat a small saucepan on low and add heavy cream, butter, and peanut butter. Stir constantly until the mixture is fully incorporated. Try not to let the mixture come to a boil.

Step 15

Pour the hot peanut butter mixture over the chocolate and whisk until all of the chocolate has melted and the ganache is smooth.

Step 16

Pour the ganache over each cake, and top with chopped dark chocolate peanut butter cups.