Preheat oven to 350 degrees. Spray a 9 x 13 inch baking dish with non-stick cooking spray.

In a bowl, combine the graham cracker crumbs with the melted butter. Stir until all the crumbs are wet. Then press into the bottom of the prepared 9 x 13 inch baking dish.

Pour the sweetened condensed milk all over the crust. Carefully spread if need to cover the entire crust.

Sprinkle 1 cup of the marshmallows over the sweetened condensed layer, followed but the chocolate chips and then the graham cracker pieces.

Place in the oven and bake at 350 degrees for 15 minutes.

Remove from oven and sprinkle with the remaining 1 cup of marshmallows. Place back in the oven and cook for an additional 10-15 minutes at 350 degrees until the marshmallows are golden brown.

Remove from oven and top with the milk chocolate bar pieces. Allow to cool completely and cut into bars. Serves 24.