I've been on a jag to see how much I can get away with pureeing baked sponge cakes. In this case, I used a dense flourless chocolate cake, and pureed it with a small amount of water until it was of a liquid consistency. That was the glass of cake part. The slice of milk, is a genoise that uses milk powder as one of its main ingredients. Once it is cooked (in a microwave, not baked in an oven) it has the flavor of the lactose in the milk powder. Cake and milk, just doing a little role-playing.
I think I got one more cake puree dessert left in me and then I will be done.