Using butter, grease the bottom and sides of two 8 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 the 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 cake flour, baking powder and salt. Set aside.
In a mixing bowl combine the butter and sugar, beat with an electric mixer until fluffy, 2 minutes. Add in the melted chocolate and eggs, beat to combine.
Place the 2 tbsp of hot tap water in a small bowl, stir in the baking soda then add to the batter. Add half of the chocolate milk to the batter, stir by hand with spatula to combine. Gradually add half of the flour mixture, mixing lightly. Repeat with the second half of the chocolate milk and second half of the flour mixture - mixing just until combined.
Divide the batter evenly between both pans, with about 2 & 1/4 cups of batter in each pan. Bake for 30-32 minutes or until a toothpick inserted in the center comes out clean.
Once the cake is done, 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.
Make sure the cake is completely cool before moving forward. If you’d like to make the cake several days in advance, wrap the cake in plastic wrap and place it in the refrigerator.
In a mixing bowl, beat the butter using an electric mixer until fluffy. Add in the cocoa powder, and gently mix by hand with a spatula.
Begin to add the powdered sugar, about 1-2 cups at a time, mixing by hand first, then with the electric mixer. Continue adding powdered sugar until the frosting tastes good to you and is well mixed.
HOW TO ASSEMBLE
Spread a small amount of chocolate buttercream on an 8 inch round cardboard cake circle (or whatever you are choosing to put your cake on). Place your first layer of cake on top of the cardboard.
Add a generous amount of buttercream on top of the first layer, covering it in an even layer.
Place the next layer of cake on top of the previous one. Evenly cover the top of the cake with buttercream. Use a small offset spatula to add a thin layer of buttercream to the sides of the cake. Don’t completely cover the cake layers as they are suppose to still be visible - however if you prefer, you can cover them fully.
Add fresh raspberries, blackberries, and chocolate shavings to the top of the cake.
Slice and serve.
*You can make your own cake flour at home by measuring out 1 cup of flour, then removing 2 tbsp of flour and replacing it with 2 tbsp of cornstarch. We sure to sift the flour and cornstarch mixture twice.