Prepare Chocolate Truffles following recipe instructions (cake as photographed used 108 3/4-in. truffles). Dip chilled truffle mixture in melted dark cocoa or white Candy Melts, then in cocoa powder, coconut or chopped nuts, as desired.
Bake your favorite 3-layer 12 in. square chocolate cake following recipe instructions. Cool completely. Stack with desired filling on square cake base.
Using spatula, ice cake smooth with chocolate icing, icing sides of cake 1/2 in. thick. Raise cake up on a turntable. Using large-tooth edge of decorating comb, comb cake sides.
Arrange truffles at corners of the cake. If needed, use dots of icing to secure truffles to the cake and each other.