This Low Calorie Brownie in a Mug is just 54 calories, and takes just 1 minute to make!I also supplied you with a topping list, so you can "jazz" up these single serving brownies however you like them!Special Tip: You can add in 1 teaspoon peanut butter, chocolate chips, or Nutella to the batter mix to change up the recipe and make it even more indulgent.