Prepare fire or heating source. You want a flat bed of coals for the best result.
Cut slit in bananas making sure not to cut all the way through. Spread open banana and stuff with chocolate chips and marshmallows. Smoosh banana back together and wrap in foil.
Place foil wrapped banana on coal bed for approximately eight minutes (rotating halfway through).
Remove from fire and let cool for a few minutes. Serve warm with a spoon.