1 cup all-purpose flour (divided)
1/2 cup unsweetened cocoa powder
1 cup granulated sugar
1/2 cup brown sugar
3/4 cup butter (melted + softened, divided)
2 large eggs
1 tsp baking soda
1 tsp vanilla extract
1/2 tsp salt
1 cup chocolate chips
Preheat oven to 350°F (175°C). Line and grease a 9×9-inch pan.
Make brownie batter: Mix melted butter, sugar, cocoa, eggs, vanilla, flour, and salt.
Make cookie dough: Cream softened butter, sugars, egg, vanilla, flour, baking soda, and salt. Fold in chocolate chips.
Spread brownie batter, top with cookie dough, and bake for 32-38 minutes.
Cool, slice, and enjoy.