Make candy clay one day in advance. Use light cocoa Candy Melts candy to prepare candy clay following recipe directions. Let set overnight.
Make cake. repare chocolate and white batters, separately, following recipe directions. Bake and cool 2-layer checkerboard cake according to pan directions. Assemble cake in checkerboard pattern according to pan directions. Place cake on foil-wrapped cake circle.
Prepare buttercream icing following recipe directions. Use spatula and white icing to ice cake smooth.
Make candy clay squares. Use 9 in. fondant roller with purple guide rings to roll out candy clay 1/8 in. thick. Use knife to cut 27 squares, 1 5/8 in. x 1 5/8 in. Position squares on iced cake.