01 -
Heat oven to 350°F (175°C). Grease and flour two 9-inch cake pans.
02 -
Whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt in a large bowl.
03 -
Add eggs, milk, oil, and vanilla extract into the dry mixture. Beat until smooth. Stir in boiling water; the batter will be thin.
04 -
Divide the batter evenly between the prepared pans. Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.
05 -
Let the cakes cool in the pans for 10 minutes, then transfer to wire racks to cool completely.
06 -
Beat butter until creamy. Gradually add powdered sugar and cocoa powder, then mix in milk and vanilla extract. Beat until the frosting is light and fluffy.
07 -
Spread frosting over the top of the first cake layer, add the second layer on top, and coat the entire cake in frosting to finish.