If you take an apple corer with you, remove the apple core and replace with a mix of brown sugar, cinnamon and raisins; wrap with aluminum foil and bake in the the coals for 10-15 minutes. If you have some extra apples, use the corer to make bottom plugs for the apples so all the stuff doesn't run out when it heats up.
Of course, if you have other people around, and need to use the campfire for your treats, that means you have to share. "Share" = give your stuff to other people. Personally, I would rather just take a large chunk of good chocolate and hoard it for myself. Don't need no stinkin' campfire!
Sue