Preheat oven to 350 degrees F. Grease a 9 by 13 pan.
Prepare the brownies according to package or recipe directions
Fold in the chocolate chips and graham crackers.
Pour half the batter into the greased pan. Spread the marshmallow fluff over the batter. Top with the rest of the batter.
Bake until a toothpick inserted in the center of the brownies comes out clean and the brownies start to pull away from the edges of the pan, about 25 -35 minutes. Cool.
You can replace the graham crackers with golden grahams which would be equally delicious and simpler if you don't want to deal with the mess of breaking up a bunch of graham crackers.If the brownie mix you are using already has chocolate chips in them, like the Ghiradelli brand, omit the additional chocolate chips called for in this recipe.