Prepare your campfire, grill, or oven. For a campfire or fire pit, let the fire burn down to glowing coals with moderate, steady heat rather than active tall flames. For a grill, preheat to medium heat (about 375–400°F). For an oven, preheat to 400°F.

If using peanut butter or Nutella, spoon about 1 teaspoon into the bottom of each waffle cone and use the back of the spoon or your finger to spread it along the interior walls of the lower third of the cone.

Layer the fillings into each cone starting with chocolate chips (about 3–4 tablespoons per cone) as the bottom layer, then a few pieces of strawberry and banana, then a generous handful of mini marshmallows. Continue layering until the cone is full, pressing gently so the filling is compact but not crushed. The marshmallows should reach or slightly exceed the top of the cone.

Tear two sheets of aluminum foil large enough to fully wrap each cone with room to tent the top. Place a filled cone in the center of the first foil sheet. Wrap snugly around the cone's sides and bottom, leaving the top loosely tented — do not press the foil flat against the marshmallows. Wrap the second sheet of foil around the first for double-layer protection.

For campfire: prop the wrapped cones upright with the tip pointing down near glowing coals or set them on a grill grate over the fire. Cook for 5–8 minutes until you can feel through the foil that the filling has softened and melted. For grill: place on the cool side of the grate, close the lid, and cook 5–7 minutes. For oven: place upright in a muffin tin and bake 8–10 minutes.

Carefully remove the cones from the heat using tongs or a heat-proof glove — the foil will be very hot. Allow to rest, still wrapped, for 60 seconds. This lets the filling settle to the perfect warm, gooey (not scalding) temperature.

Unwrap the foil carefully, peeling it back from the top. The filling should be fully melted, the marshmallows golden and puffed, and the cone slightly softened but still holding its structure. Serve immediately and enjoy over the foil as a natural drip catcher.