Preheat oven to 350°. Line a 9x13” pan with foil and spray with cooking spray.
If you’re using a brownie mix, prepare as directed on the box. Set aside.
If you’re making from scratch brownies: Place the two baking chocolates and butter in a large, microwave safe bowl. Heat on HIGH power for 2-3 minutes, stirring every 30 seconds, until chocolate is smooth. Stir in sugar. Add eggs, vanilla, and cocoa and stir well. Add flour and stir carefully. Set aside.
Make the cookies: Cream together butter and sugar in the bowl of a stand mixer or in a large bowl using a hand mixer. Mix in egg, extracts, baking soda, and salt. Stir in flour, then stir in food coloring if using, being sure to scrape the sides of the bowl to make sure all the dough gets turned green. Stir in the chocolate chips.
Spread brownie batter in prepared pan. Scoop tablespoons of cookie dough, flatten slightly with your hands and then lay over the top of the brownies. It’ll be hard to spread because it’s thicker than the brownie batter, so it’s best to drop flattened tablespoons evenly over the batter and then press lightly with your fingers to adhere them to each other.
Bake for 30-40 minutes until the tops are starting to get golden. The toothpick test in the center will come out with some crumbs on the toothpick.
Cool completely before cutting into small bars. These are some serious brookies - a little goes a long way!