Preheat oven to 450°F.

Rub the inside of a 10-inch oven-safe skillet or baking dish with butter.

Spread chocolate chips in an even layer across the bottom of the skillet.

Pile mini marshmallows on top in a thick, even layer covering all the chocolate.

Bake for 8 to 10 minutes until marshmallows are puffed and golden and chocolate is melted underneath.

Serve immediately in the skillet with graham crackers for dipping.