Step 1

Preheat the oven to 350 degrees Fahrenheit. Grease 2 (9-inch) round baking pans with oil or butter and lightly coat with flour.

Step 2

In a large bowl, sift together the sugar, flour, cocoa powder, baking powder, baking soda, and salt.

Step 3

Beat in the eggs, milk, oil, and vanilla. Beat for 2 minutes on medium speed, or until the mixture is smooth and lump-free. Stir in boiling water. The batter will be very thin.

Step 4

Pour the batter into greased pans. Bake for 30 to 35 minutes or until a toothpick inserted into the center comes out clean.

Step 5

While the cakes are in the oven, prepare the frosting. Stir the butter and cocoa powder in a bowl. Add in powdered sugar and milk alternately. Beat the frosting until spreadable, adding more milk if needed. Stir in vanilla extract.

Step 6

Let the cakes sit for 10 minutes. Transfer them into wire racks to cool completely.

Step 7

To assemble the cake, place the first layer onto a flat serving plate. Using an offset spatula, spread a 3rd of the frosting evenly on top of the cake.

Step 8

Top the frosted cake with the 2nd cake. Spread remaining frosting on top and the sides of the cake.

Step 9

To make a one-pan cake, use a 13x9x2-inch pan. Bake for 35 to 40 minutes at 350 degrees Fahrenheit.

Step 10

To make a three-layer cake, use 3 8-inch round baking pans. Bake for 30 to 35 minutes at 350 degrees Fahrenheit.

Step 11

To make a bundt cake, use a 12-cup fluted tube pan. Bake for 50 to 55 minutes at 350 degrees Fahrenheit.

Step 12

To make cupcakes, line muffin tins with cupcake liners and fill them 2/3 full. Bake for 22 to 25 minutes at 350 degrees Fahrenheit. One recipe makes about 30 cupcakes.