Spray a 13×9 pan with cooking spray and line with parchment paper, leavingsome extra over the sides. Melt butter over medium heat. Once its melted reduce heat to low. Reserve 1 cup of mini marshmallows from the 10 oz bag and also a small handful for sprinkling on top. Add remaining marshmallows to pot. Spray a mixing spoon with cooking spray and continuously stir until marshmallows are fully melted. 

Remove pot from heat and add the Golden Grahams. Stir to combine. Add remaining marshmallows and 1 cup of chocolate chips. Stir. Gently push into and even layer in the pan. Top with extra marshmallows and chocolate chips and let set in refrigerator. Once set, pull parchment paperand slice. Store in an air tight container.