For the Cake

Cup of Yum
1. Preheat the oven to 350°F. Coat the sides of two 8-inch round cake pans with butter, and then sprinkle a light dusting of cocoa powder over the butter. Set the pans aside until the batter is ready.
2. In a medium bowl whisk together the cocoa powder and the boiling water. (If the mixture is too thick, add in 1 tablespoon of hot water until it looks like creamy chocolate frosting. Once it is well combined, allow the mixture to cool for about 2-3 minutes. Once it has cooled, whisk in the milk until it is smooth and creamy, then set aside. (The mixture should be similar to very chocolate hot cocoa, or dark chocolate milk. Be sure to whisk until all of the cocoa powder is dissolved.)
3. In a medium bowl, whisk the flour, baking soda, and salt. Set aside.
4. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar together until creamy. Continue mixing on low, adding in the vanilla, then the eggs.
5. Add the cocoa mixture to the butter mixture, mixing on medium speed until it is all well combined. Add in the flour mixture in batches, while mixing on low to medium speed. Continue mixing until the batter is smooth and creamy.
6. Evenly divide the batter into the two prepared pans (about 596 grams per pan) and bake for about 28-30 minutes, until a toothpick comes out clean or the top of the cake springs back when touched.
7. Remove from the oven and allow the cakes to cool before frosting.

For the Frosting

1. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter with the cocoa powder until well combined and creamy.
2. With the mixer on low speed, slowly add in the powdered sugar, 1 cup at a time, allowing it to be mixed in. Use a rubber spatula to scrape the sides of the bowl if necessary. 
3. Add in 3 tablespoons of the milk, and the vanilla, allowing the frosting to become smooth. Add in additional milk, 1 tablespoon at a time, until it reaches your desired texture. 
4. Spread a layer of frosting on top of 1 layer of cake, top with the second layer of cake, then frost around the cake and decorate as desired.