For mine I used peanut butter and Nutella, Nutella and mini marshmallows, and Nutella with sugar and cinnamon sprinkled on top.
My favorite: Nutella with cinnamon and sugar on top! Surprisingly, I liked it better than the peanut butter and Nutella (which is usually my favorite combination, ever!).
Such a quick, simple, and cheap treat that would be great for a Christmas Eve snack for Santa. He might enjoy a little change-up from the normal cookies. :)