Preheat waffle iron to medium heat.
Prepare waffle mix according to package instructions.
Spray the waffle iron with nonstick cooking spray on both plates. Scoop 1/3 cup brownie batter onto the center of the waffle iron and close the lid.
Cook for 6 to 8 minutes, until the waffle iron stops steaming.
Carefully remove the waffles from the waffle iron and allow to cool completely before serving.