Cake serves 9.
Bake your favorite cake recipe or mix in loaf pan. Cool cake in pan on wire rack 10 minutes. Remove from pan and cool completely. Place on foil-wrapped cake board. Position cake on turntable.
Prepare buttercream and chocolate buttercream recipes. Combine a portion of white buttercream with a portion of chocolate buttercream icing to create a light chocolate shade. Spatula ice cake smooth with light chocolate buttercream; icing on cake sides should be about 1/2-inch thick. Comb cake sides with wide-tooth edge of Decorating Comb.
On cake top, decorate alternating rows of tip 16 dark chocolate buttercream and tip 21 white buttercream shells. Add tip 21 white shell bottom border.