Using a knife, cut out a small strip of peel from the top of your banana, leaving one end intact. Pull back the strip, and use a knife or spoon to carve a shallow "canyon" down the center of your banana. Eat the piece of banana you carve out. :)
Fill the canyon with chocolate chips and marshmallows and other mix ins if desired. Stuff it as full as you can! You can also smear some peanut butter or Biscoff spread on before you start.
Place the peel back into place then wrap a square of foil tightly around the banana.
Set foil packets directly on the grill, cover, and cook for 10-12 minutes or until marshmallows and chocolate are melted.
Remove from the grill and carefully pull away foil. It may take some marshmallow with it...don't worry! Pull back the peel and dig in!