Crush the Golden Grahams so you have a combination of fine and larger pieces.
Melt the butter in a large pot over medium heat. Add the marshmallows and cook until they melt completely.
Mix in the crushed Golden Grahams. Coat completely with the melted marshmallows.
Pour the mixture into a 9x13-inch pan coated with cooking spray.
Spray a piece of wax paper or parchment with a little cooking spray and press it against the top of the mixture to flatten it into one layer. Remove the paper.
Sprinkle the flattened mixture with milk chocolate chips.
Let cool completely for at least 1 hour, then cut into squares.