6 tablespoons butter, softened
Cocoa powder, see below
2 2/3 cups powdered sugar
1/3 cup milk
1 teaspoon vanilla extract
For light chocolate frosting use 1/3 cup cocoa powder. For medium chocolate frosting use 1/2 cup cocoa powder for dark chocolate frosting use 3/4 cup cocoa powder.
In mixer bowl cream the butter. Add the cocoa and powdered sugar alternately with milk. Beat to spreading consistency adding more milk if needed. Blend in vanilla.
This makes about 3 1/4 cups. You will need to double it or triple it for the 3 layer cake.