In a medium sized bowl, mix sugar mix and graham cracker crumbs until combined.
Pour melted butter over dry mixture. Do NOT follow the instructions on the bag to add any other ingredients.
Press into an ungreased 13×9 inch pan to make the crust. Bake in a 375 degree oven for 18-20 minutes, until golden brown and set.
Sprinkle the chocolate chips on top and wait about 3 minutes for them to melt. Spread evenly over the crust.
Top with marshmallows and broil for 30 seconds or until browned, watching carefully so you don't burn the marshmallows.
Allow to set for a few minutes and then cut and serve.
Notes
To keep from ruining the marshmallow topping, dip your knife in VERY HOT water before drawing through to slice. Wipe off whatever excess sticks to the knife, dip in water again, and slice.