Banana Coconut Caramel Upside-Down Cake (and uses a boxed cake mix) yuummmm but without the coconut!
Slice potato almost but not all the way through. Tuck butter between slices. Bake until tender. Dribble with sour cream. Shower with grated cheese. Bake again until melted and gooey. Lavish with more sour cream and chopped scallion or chili or whatever you please.