Preheat the oven to 350°F
Line an 8×8-inch or 9×9-inch baking pan with parchment paper or grease it well
Prepare the brownie mix according to the package directions
Spread the brownie batter evenly into the prepared pan
Cut or scoop cookie dough into small portions
Place the cookie dough pieces evenly over the brownie batter
Gently press the cookie dough pieces slightly into the batter
Bake for 25 to 35 minutes, or until the brownie layer is set and the cookie layer is lightly golden
Check for doneness with a toothpick inserted into the center
Let the brookies cool completely in the pan
Lift out and cut into squares
Serve once cooled