Preheat the oven to 350°F (175°C). Spray two muffin pans (24 wells total) generously with nonstick cooking spray.

In a large bowl, prepare the brownie batter by following the instructions on the brownie mix box.

Add an extra egg to the batter for a chewier texture.

Pour the brownie batter evenly into the muffin wells, filling each about 2/3 full.

Bake in the preheated oven for 20 minutes, or until a toothpick inserted comes out with a few moist crumbs.

Let the brownie muffins cool for 5 minutes in the pan before carefully removing them.

Use the tip of a butter knife to pop them out if needed.

Serve warm or at room temperature and enjoy the perfect combination of crispy edges and chewy centers!