preheat oven to broil. Line a baking sheet with foil. Place marshmallow halves on prepared baking sheet. Place baking sheet on rack closest to heating element. Broil for one minute, or to desired degree of doneness. Cool marshmallow on pan for one minute.
Place half of marshmallow on top of half of chocolate graham crackers. Place peanut butter cup on top of marshmallow. Top with remaining marshmallow half in graham cracker. Serve at once. Makes one serving.