Preheat oven to 350 degrees Fahrenheit. Grease and line with parchment paper a 8x8 or 9x9 baking pan.

Mix the graham cracker crumbs and sugar. Then add butter just until combined. Add to prepared pan, pressing into an even layer. Bake for approximately 15 minutes, or until golden brown.

While the graham cracker base bakes, prepare your brownie mix according to the back of the box. Once prepared, add the chocolate chips.

Once the graham cracker crust has baked and cooled slightly, pour the brownie mixture on top and spread evenly. Cook according to the back of the brownie box.

As soon as the brownies come out of the oven, top with the marshmallows and pop back in the oven. When the marshmallows begin to puff and melt, switch to the oven broiler to give the brownie a nice toast. You’ll want to watch closely to be sure the marshmallows don’t burn. You want that dark brown color that will give the marshmallows that s’mores taste and texture.

Optional: Nestle pieces of graham crackers and chocolate into the marshmallow mixture.

Cool completely and then cut into squares. Store in an air tight container.