We made fossil cookies. I used a thick GF/CF shortbread base, to minimize spreading while baking. The kids mixed, measured, and stirred. They pressed plastic dinosaurs into the cookies to make imprints and then baked them. When cool, they dusted them with cocoa powder (okay, the concept here was to use a brush. They ended up brushing ON cocoa instead of brushing OFF dust from a fossil, but I think they got the idea). And, of course, then they ate them.