Set a large pot over medium to medium low heat. Add the butter and once melted pour most of the bag of marshmallows (save some for the topping).

Stir until the marshmallows are melted, remove from heat, and stir in the Golden Grahams cereal. Once slightly cooled for just a minute or two, stir in most of the chocolate chips, saving some for the topping.

Spray a 9x13 casserole dish with non stick spray and spread the dessert evenly. Add the remaining marshmallows and put in the oven turned to the broil setting just for about a minute to toast the marshmallows.

Add the remaining chocolate chips right away so they melt slightly over the top. Let this cool completely before cutting into bars and serving.