Set oven rack about 6 inches from the heat source and preheat the oven's broiler.
Place 1 graham cracker square in each of 4 miniature cast iron skillets. Top each graham cracker square with 1 piece of chocolate, and 1/2 marshmallow.
Place skillets in the preheated oven and cook until marshmallows begin to brown, about 3 minutes.
Remove miniature skillets from oven and gently press marshmallows into chocolate with a spatula.
