Preheat the oven to the brownie package directions and grease an 8x8 baking dish with baking spray.
Prepare the brownie mix according to the directions on the box and pour it evenly into the prepared baking dish.
Bake for the time it says on the back of the box for an 8x8 dish.
Remove the brownies from the oven and spread the marshmallows evenly over the top of the brownies.
Set the oven to broil and place the baking dish back into the oven for 30-40 seconds.
FOR THE FULL RECIPE