For each serving you will need:
a handful of mini marshmallows
a handful of chocolate chips
Pre-heat oven to 350 degrees. Peel the banana and slice it nearly in half. Place the banana on foil and open it slightly (it's okay if it breaks in half). Sprinkle with marshmallows and chocolate chips. Wrap tightly in foil and bake in preheated oven for 5 to 10 minutes (until you've reached your desired level of gooey meltedness).
Open the foil and enjoy!