Craving the symbol of old-timey ice cream parlors but missing a key ingredient, ice cream? Well, even if you aren't, you should make this and eat it anyways. It is yummy, easy, and fast to make. Don't let the garish black peel scare you off, obviously you don't eat that. The peel is simply the vessel in which warm, gooey, sugar heaven is preserved until reaching your mouth via spoon.
(everything that follows is optionable, tweakable, etc. The flavor combinations are only limited to what you find in the cupboard)
Sweetened shredded coconut
Peanut butter chips
(other fillings: butter and brown sugar, dried fruit, candy pieces, nuts...)
Heat oven to 350-375 deg. F (depending on how firm/mushy you want the banana). Cut off banana stem. Slit peel at base of banana (where stem would be) and slit lengthwise cutting into fruit, but not through the peel on the other side. Fill center with anything that pleases your fancy. My only suggestion would be, if you are using marshmallows, save that for the very top, as that creates a nice crunchy crust that is fun to crack into, and that also helps to keep everything below from melting out.
Prop bananas up on an upside down donut or muffin pan. Bake for 8-12 minutes. You can tell when the bananas are done because the skin will have turned black, and the bottom of the banana should be soft to touch. If you are worried about the marshmallows burning, drape tin foil over top in last 2 minutes of baking. Serve warm.