Two beloved desserts come together in one perfect bar cookie.
1 box brownie mix, prepared according to package instructions
(feel free to sub homemade brownie if you prefer!)
12 tablespoon butter (1 1/2 sticks) melted and cooled until warm
1 cup brown sugar (light or dark)
1/2 cup granulated sugar
1 large egg plus 1 egg yolk
2 teaspoons vanilla extract
2 cups plus 2 tablespoons flour
1/2 teaspoon baking soda
1/2 teaspoon salt
1 1/2 cups semi-sweet or bittersweet chocolate chips
Preheat oven to 325 degrees. Line a 9×13 pan with foil for easy clean-up and spray with non-stick spray.
Prepare brownie mix according to package instructions and pour into prepared pan. Do not bake yet.
In your empty brownie bowl, add melted butter, brown sugar, egg and yolk, and vanilla an stir to combine. Add flour, soda, and salt and stir. Finally fold in chocolate chips until just mixed.
Use your hands to drop dough onto the top of the brownie batter, it’s okay if some brownie batter shows through.
Bake for 25-30 minutes until cookie part looks set, but not crunchy and brown. You can poke with a skewer or tooth pick to see if the brownie layer is done. You really need to eyeball since all brownie mixes are a little different! I’m using one that is meant to be baked in a slightly smaller pan so if you use a mix meant for a 9×13 it might need a little longer. Cool, cut, and serve.
If you look on the back of the box, some brownies have instructions for a 9×13 pan, and some say the largest pan option is 8×8 or 9×9. Either of those is just fine. with the 9×13 you will have a thicker layer of brownie. In these photos I’m using a box that makes the latter, smaller batch, and I still baked in a 9×13 and I feel like it’s a good size brownie layer.