1-Preheat oven to 350°F (175°C): Line a 9×13 inch baking dish with parchment paper or foil.

2-Make Brownie Batter: Melt butter and stir in cocoa powder. Whisk in granulated sugar, light brown sugar, and salt, then add eggs and vanilla, beating until glossy. Stir in flour until almost combined, and fold in 3/4 cup semi-sweet chocolate chips or chopped chocolate. Spread the batter evenly in the prepared pan.

3-Make Cookie Dough: Cream room temperature butter, granulated sugar, and light brown sugar until light and fluffy. Beat in vanilla and egg, then add salt, baking powder, and baking soda, mixing until combined. Stir in flour until just combined, and fold in 1 cup semi-sweet chocolate chips, saving a few for the top if you like.

4-Assemble and Bake: Drop spoonfuls of cookie dough over the brownie batter, leaving some brownie visible. Cover the dish with foil and bake for 20 minutes, then remove the foil and bake for another 20 minutes.

5-Cool and Serve: Let the brookies cool completely in the pan before slicing them into bars for the perfect texture.