Preheat and prepare:
Preheat your oven to 350°F (175°C). Line an 8×8 inch baking pan with parchment paper and grease the sides to prevent sticking.

Prepare cookie dough base:
Press the cookie dough evenly into the bottom of the prepared pan, making sure it fully covers the base.

Mix the brownie batter:
In a medium bowl, prepare the brownie mix according to the package instructions. For a more cake-like texture, you can add an extra egg, but be sure to increase the baking time slightly if you do.

Assemble and add topping:
Pour the brownie batter over the cookie dough layer, spreading it evenly. Sprinkle the mini chocolate chips evenly over the top.

Bake and cool:
Bake for 50 to 55 minutes, or until the top is crinkly and a toothpick inserted comes out with a few moist crumbs. Remove from oven and place the pan on a wire rack to cool completely.

Serve:
Once cooled, cut into squares and serve alone or with ice cream for an extra indulgent treat.