Using butter grease the bottom and sides of three 6 inch round cake pans or springform pans and line the bottoms with a round piece of parchment paper. To ensure even baking, place a bake even strip around each pan. You can make your own homemade bake even strip by cutting a towel or shirt to fit the size of your pan. Get the fabric really wet, then squeeze out the dripping water but do not squeeze it too dry. Secure the fabric around the pan with a safety pin.
In a small mixing bowl, combine the cocoa powder, flour, baking powder, baking soda and salt. Gently mix using a spoon.
In a larger mixing bowl, combine the butter and sugar, beat using an electric mixer until fluffy. Add in the eggs and vanilla, lightly beat.
Add in the sour cream and melted chocolate, mix by hand using a spatula.
Add half of the flour mixture to the wet ingredients, do not dump it in, rather take spoonfuls of the flour mixture and gently shake it over the wet ingredients. Fold in the mixture until no flour remains. Repeat with the other half of the flour, folding it in and scraping the sides and bottom of the bowl to incorporate everything.
Evenly divide the batter between the 3 pans, with about 1 & 1/3 cups to 1 & 1/2 cups in each pan.
Bake for 22 minutes. Then loosely cover the pans with foil. Continue to bake for 7-10 minutes or until a toothpick inserted in the until a toothpick inserted in the center comes out clean.
Once the cake is done baking, allow it to cool in the pan on a cooling rack for 10 minutes. After 10 minutes, carefully remove the cake from the pan. If using a springform pan, remove the sides and bottom. Allow the cake to cool completely on a cooling rack. Once cool, remove the parchment paper round from the bottom of the cake. If you need to level the top of your cake, do so now using either a cake lever or knife.
If you’ll be assembling the cake later, wrap the cake layers really good in plastic wrap and place them in the refrigerator. They will be good for up to 5 days.
Peppermint Buttercream
In a mixing large bowl, combine the butter and vegetable shortening, beat using an electric mixer until fluffy, 2 minutes.
Add in the peppermint extract and crushed candy canes, beat using electric mixer.
Begin to add the powdered sugar, about 1 cup at a time, mixing by hand first, then with the electric mixer. Continue adding powdered sugar until the frosting tastes good to you.
Chocolate Ganache
Place chocolate chips in a medium heat-proof bowl.
In a small pot over low heat, heat the heavy cream until boiling.
Pour the heavy cream over the chocolate chips. Allow the mixture to stand for 1-2 minutes.
Use a spatula to stir the mixture until smooth.
Allow the ganache to come to room temperature before adding it to the cake.
Spread a small amount of buttercream on a 6 inch round cardboard cake circle. Place your first layer of cake on top of the cardboard. Put buttercream on top of the first layer and spread it as even as possible with an offset spatula. Decide how much or how little frosting you want in-between each layer, you can measure the frosting, I use 1/3 to 1/2 cup in between each layer.
Repeat this process for each layer of cake. Once all of the layers are stacked and frosted, spread some frosting (the same amount as you did between the layers) on the top of the cake.
Next, it’s time to do a crumb coat. The crumb coat will help seal the crumbs in. Using your offset spatula, spread a thin layer of buttercream around the sides and the top of the cake. It’s easiest to start off with more frosting on the cake and remove some as needed.
Place the entire cake in the freezer or fridge for 20 minutes to harden the crumb coat.
Begin to add the second layer of frosting. Spread an even layer of frosting on the top of the cake. Next spread the frosting around the sides of the cake. I used a small offset metal spatula to give the frosting a textured look.
Transfer the cake to your desired serving plate. Using a piping bag and a piping tip (I used a wilton 1M) to pipe a border of buttercream around the bottom of a cake.
Once the ganache is room temperature, use a spoon to drizzle the ganache around the sides of the cake, allowing it to drip down the sides. Fill in the middle of the cake with ganache and spread evenly with the back of the spoon. Allow the ganache to set for 10 minutes.