Preheat oven to 350º F. Spray a 12-cup cupcake/muffin tin with cooking spray.
Prepare the boxed brownie mix according to directions, using the required ingredients.
Divide the brownie batter into the prepared muffin tin then bake 25 - 30 minutes, until toothpick inserted comes out clean.
Spray the bottom half of a second 12-cup muffin tin with cooking spray.
Once the brownies have baked, remove from the oven and immediately press the second muffin tin into the brownies. Keep both tins pressed together until the brownies are cool.
Once cooled, remove the brownie cups and top with a scoop of delicious Ben & Jerry's Ice Cream and any additional sundae toppings. Serve and enjoy!