Part 3: Make the Chocolate Frosting
Beat the butter – In a large bowl, beat the softened 1 cup butter until creamy and smooth.
Sift dry ingredients – In a separate bowl, sift together the powdered sugar and cocoa powder.
Combine alternately – Gradually add the sifted dry mixture to the butter, alternating with the ⅓ cup milk. Begin and end with the dry mixture. Beat well after each addition.
Add vanilla – Mix in the 1 teaspoon vanilla extract. Beat until light and fluffy. If the frosting is too thick, add more milk (1 teaspoon at a time). If too thin, add more powdered sugar.
Part 4: Assemble the Cake
Level the layers – If your cake layers have domed tops, use a serrated knife to slice them flat.
