Line each cone with peanut butter if you wish. Place a couple marshmallows on the bottom of the cone to the toppings don't melt out of the bottom of the cone. Then fill with your favorite toppings. I used chocolate chips, mini marshmallows, graham cracker pieces and peanut butter. Wrap each cone tightly with foil.: The warm aroma of peanut butter is nutty and inviting, and when spread inside the cone it creates a glue like barrier that helps keep other fillings from sliding out. I use the back of a spoon to smear a thin layer, feeling the slight resistance as it spreads, which tells me I have enough. This also adds a savory counterpoint to the sweet components, rounding the overall flavor. A mistake to avoid is applying too thin a layer, which will not prevent fillings from shifting, or too thick a layer, which can overwhelm the texture and make the cone heavy.
Bake at 375 degrees Fahrenheit for 5-7 minutes.: Tucking a few mini marshmallows into the cone base creates a soft plug that puffs and becomes slightly sticky as it warms, audible in the faint pop and crackle of melting pockets. This creates a foundation that keeps chocolate and crumbs from seeping out. You want just enough to form a seal, so the cone still feels balanced in your hand. Do not overstuff the bottom because the marshmallow expansion can push other fillings out during cooking.
Preheat the grill to medium high heat and place the cones on the grill grates for 5-10 minutes, turning occasionally.: Layering feels tactile and playful, with the glossy chocolate chips sitting beside pillowy marshmallows and crunchy graham cracker pieces . I alternate textures so each bite has contrast, pressing lightly to compact the fillings but not so much that the cone cracks. The visual cue is a full but not overflowing cone, with ingredients visible at the top. A common misstep is packing too tightly which prevents even melting and makes the cone hard to re wrap neatly.
Heat the foil-wrapped cones over a campfire for about 3-5 minutes, or until the chocolate and marshmallows have melted.: In my trials this combination produced a perfect balance, with melted chocolate chips pooling around toasted mini marshmallows , while the graham cracker pieces kept the texture interesting and the peanut butter adding savory depth. When heated you will notice a sweet scent of toasted sugar and warm chocolate. If your fillings are cold from refrigeration, allow them to sit briefly so they meld more efficiently during heating. Avoid using cold wet fruit without accounting for the extra moisture they add.
Wrap each cone tightly with foil: Wrapping in aluminum foil seals in heat and steam, and when I fold the foil it makes a muffled crinkle sound that tells me the cone is snug. This trapped heat ensures the chocolate chips soften and the mini marshmallows toast without burning. Make sure the foil is sealed all the way around, especially at the tip, so nothing leaks out. A loose wrap can expose fillings to direct flame or grill heat, which can scorch them quickly.
Bake at 375 degrees Fahrenheit for 5-7 minutes: In an oven the air becomes evenly warm, and you will smell a gentle caramelizing of sugars as the mini marshmallows puff and the chocolate chips melt into glossy ribbons. The exterior of the waffle cones may warm and deepen slightly in color. Use the shorter time for softer melts and the longer time for more gooey melding. A common error is leaving them too long, which can dry out the cone and make the marshmallows tough rather than soft.
Preheat the grill to medium high heat and place the cones on the grill grates for 5-10 minutes, turning occasionally: On a grill the sound is different, a faint hiss as the foil warms and smoke adds a subtle toasty note, while you turn each cone so heat kisses every side evenly. You are listening for a gentle sizzle through the foil and watching for a warm steam to escape when you peek, indicating the fillings are melty. Turn periodically to avoid hot spots and toasts forming on one side only. Avoid placing the cones directly over an open flame without foil, as that will char the cone quickly.
Heat the foil-wrapped cones over a campfire for about 3-5 minutes, or until the chocolate and marshmallows have melted: Campfire heating is immediate and aromatic, with wood smoke layering over the sweet scents of melting chocolate chips and caramelizing mini marshmallows . Hold the cones at a safe distance from the embers and rotate them slowly, feeling warmth through the foil until you sense even heat. The cone should be hot to the touch through the foil but not overly scorchy, and the fillings should be visibly melted when you carefully unwrap. A frequent mistake is leaving them too close to coals, which can burn the foil and produce bitter flavors.