Powdered sugar and cocoa powder can be used singly or in combination to give a frosted cake a polished look. When using stencils of any sort, freeze the cake for 15 minutes before decorating. Powdered sugar will gradually dissolve, so apply this fancy decoration just before serving. Gather six jar lids, varying in size from small to medium. Place the lids facedown on the surface of the cake in a random arrangement, letting some hang over the edge. Dust the cake with cocoa or confectioners’ sugar. Remove the lids, grasping them by the lip and lifting straight up. Rearrange them randomly again, then dust with a contrasting color, using confectioners’ sugar, cocoa, or very finely ground nuts. Remove the lids carefully. Click here for more cake tips.