Trim bottom layers; stack on cake round, with 3/4 cup buttercream spread over top of each. Add top layer; spread 1 cup buttercream over entire cake. Refrigerate 40 minutes until firm. Tint half remaining buttercream pink.
Place cake on rotating stand. Lay flat a 12-inch pastry bag with #103 tip. Fill half of bag from tip to top with pink buttercream, other half with white. Hold bag vertically, slot of tip perpendicular to cake; use swift back-and-forth motion 1 inch wide to make ruffle, pulling tip up side.
Turn cake stand slowly, piping circular ruffle over top.
Ruffled Tower Cake inspired from Martha Stewart. Make your favourite Cake and Frosting Recipes or get the recipes from here.