Place waffle cones upright and prepare all ingredients before starting.
Add a small layer of mini marshmallows at the bottom of each cone.
Add chocolate chips on top of the marshmallows.
Add banana slices and chopped strawberries.
Continue layering until the cone is filled, leaving a little space at the top.
Gently press the filling down so it fits well but is not packed too tightly.
Wrap each cone completely in aluminum foil, sealing all sides tightly.
Place wrapped cones on a grill or over a campfire using medium heat.
Heat for 5 to 10 minutes, turning every few minutes for even cooking.
Remove from heat carefully using tongs.
Let the cones cool for a few minutes before opening the foil.
Unwrap slowly and serve warm.