Place graham cracker halves on a baking sheet lined with parchment paper.
Top each cracker half with a square of milk chocolate and a marshmallow.
Place the baking sheet under the broiler for 1-2 minutes until marshmallows are golden brown and chocolate begins to melt. Watch carefully to avoid burning.
Remove from oven and sandwich with another graham cracker half. Serve immediately.
Notes
For extra flavor, try adding a sprinkle of sea salt or using dark chocolate instead of milk chocolate.