Mix together the graham cracker crumbs with the melted butter. Line a square baking pan (8x8 or 9x9) with aluminum foil. Press the buttered graham cracker crumbs firmly into the bottom of the foil lined pan.

Prepare the brownie mix according to the box directions. Spread the brownie batter over top of the graham cracker crust. Bake according to the box directions, reducing the baking time by 3 to 4 minutes.

Once baked, sprinkle on the milk chocolate chips & mini marshmallows. Set the oven to broil, and broil the brownies for 1-2 minutes until the marshmallows are nice and toasty.

Let cool in the pan for 5 minutes before lifting out the aluminum foil to remove the brownies.