FROSTING: Make both batches of the vanilla buttercream, set aside 1-½ cups, and tint it black. The color improves while sitting, so you can make this a day or two ahead of time. Refrigerate if making ahead.

ARMS: Start by pressing rice crispies into three rectangles, about 3 in by 6 in by 2 in. Mini loaf pans are about the right size for this. Shape the two arms with your hands, compacting the rice crispies until they are almost rock hard. Set aside and allow to dry completely for a day a or two. Use the remaining rectangle for the helmet.

HEAD: Press rice crispies into the greased bowl, compacting the rice crispies as much as possible, until it is completely full. Turn the molded shape out onto a nonstick surface. Use your hands to press and mold the crispies into the shape of the helmet, using a small knife to shave where necessary. Shape the remaining “arm” of rice crispies into the shape for the top of the helmet and press it into place. Take the shaved extra bits and form into a 4 in by 1 in tall “cookie” that represents the neck. Allow to dry completely for a day or two.

CAKES: Cut one sheet cake into thirds (about 4 inches) widthwise. Cut two pieces from the other sheet cake, one 6 inches wide and one 4 inches wide (there will be about a 2 in strip leftover). Place the 6 inch piece on a small piece of wax paper on the serving platter/pizza pan, then add a layer of frosting. Stack the three equal pieces of cake on top, adding frosting between the layers, then finally top with the single 4-inch wide layer. The layers should line up along the back of the cake with the bottom layer protruding on one side to form the feet. Cut some of the cake away in the middle of the feet section to define the feet. Take the two half-inch 8-inch long dowel rods and press them down through the layers, one in each leg. This will help stabilize the structure. (The chopstick in the photo didn’t work and was replaced with the dowels.)

Use a serrated knife to trim the cake edges to make them even, trim the sides a bit to shape the shoulders. Cut a notch through the front and back of the bottom two layers to define the legs. Use the angled spatula to apply a thin crumb layer of the white buttercream all over the cake, then allow it to set up, about 30 minutes or more, overnight is even better. Apply the final layer of white buttercream once the crumb layer is set. While the frosting is still wet, smooth it all over with a wet paper towel using a paper-mache technique and gently pulling, not sliding off, this will give you a more smooth, fondant-like finish. Allow the buttercream to set up, about 30 minutes. Pipe the black decorations on the chest and back.

Apply the white buttercream on the arms, then coat the hands in black. While it’s still wet, smooth it all over with a wet paper towel similar to above, then allow the buttercream to set up, about 30 minutes.

Apply the white buttercream all over the head, then smooth it all over with a wet paper towel and allow the buttercream to set up, about 30 minutes. Then pipe the black decorations on the helmet.

Attach the arms using the chopsticks. Put one through the upper arm and one underneath the hand hook.

Place the round rice crispy neck base on the stormtrooper shoulders, centering it. You may need to cut space for the dowels.

Gently place the head on top of the cookie, balancing it in place. (We usually put a dab of frosting on something like this to hold it in place, but it didn’t work with the rice crispies.) You’re done!