For the frosting: 1/2 cup unsalted butter, 2 cups powdered sugar, 3/4 cup unsweetened cocoa powder, 1/3 cup whole milk, 2 teaspoons pure vanilla extract
Instructions
Preheat the oven to 350 degrees F and grease and flour two 9-inch cake pans.
In a large bowl, mix together the cocoa, flour, sugar, baking powder, baking soda, and salt.
Add the eggs, milk, oil, and vanilla and mix until smooth.
Stir in the boiling water until well combined.
Pour the batter evenly into the prepared pans and bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
While the cakes are cooling, make the frosting by beating the butter, powdered sugar, cocoa, milk, and vanilla until fluffy.
Once the cakes are cool, frost one layer, top with the second layer, and frost the top and sides of the cake.
Notes
The cake batter will be very thin, but this is what makes the cake moist.
Make sure to let the cakes cool completely before frosting.
If the frosting is too thick, add a little more milk.