What's better than sharing cake with friends? The look on their faces when they discover your sponge cake is made of actual sponges!
Use a marker to draw large circles on new kitchen sponges, then cut out the circles.
Stack and frost them (we used inexpensive canned frosting). Cover the sides with sprinkles, if you like.
Tell your victims that you "made a sponge cake," and invite them to cut off a piece. To help ease the prank's sting, serve real cake afterward.