Brookies (Brownie Cookies)

Preheat oven to 350 degrees F (175 degrees C).

Grease a 9x13-inch baking dish.

Beat softened butter, light brown sugar, 1/4 cup white sugar, and 1/2 teaspoon vanilla extract together in a large bowl until creamy.

Add 1 egg; beat until light and creamy, about 2 minutes.

Whisk 1 1/4 cups flour, 1/2 teaspoon salt, and baking soda together in a bowl.

Gradually stir flour mixture into butter mixture until dough is combined.

Stir chocolate chips into dough.

Spread dough into the bottom of the prepared baking dish to cover completely.

Stir 1 cup white sugar, melted butter, and 1 teaspoon vanilla extract together in a bowl; add 2 eggs and beat well.

Mix cocoa powder into butter mixture until well-combined.

Stir 1/2 cup flour, baking powder, and 1/8 teaspoon salt into cocoa mixture until batter is combined.

Pour brownie batter over cookie dough and spread to cover completely.

Bake in the preheated oven until a toothpick inserted into the center of the brookies comes out clean, 20 to 25 minutes.

Cool completely before cutting into bars.