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1. Preheat your oven to 350°F (175°C). Grease a 9×9-inch baking pan or line it with parchment paper for easy removal later.
2. In a medium saucepan, melt the 1/2 cup of unsalted butter over low heat. Once melted, remove it from the heat and stir in the granulated sugar until well combined.
3. Add the eggs one at a time, mixing well after each addition. Then, stir in the vanilla extract.
4. In a separate bowl, whisk together the cocoa powder, flour, salt, and baking powder. Gradually add this dry mixture to the wet ingredients, stirring until just combined. Be careful not to overmix!
5. If you’re using chocolate chips, fold them into the brownie batter now. Set the brownie batter aside while you prepare the cookie layer.
6. In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until the mixture is light and fluffy. This should take about 2-3 minutes using an electric mixer.
7. Add the egg and vanilla extract to the butter-sugar mixture, mixing until fully incorporated.
8. In another bowl, whisk together the flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, mixing until just combined. Again, be careful not to overmix!
9. Fold in the chocolate chips, ensuring they are evenly distributed throughout the cookie dough.
10. Now that both layers are ready, it’s time to assemble the brookies! Start by pouring the brownie batter into the prepared baking pan, spreading it evenly across the bottom.
11. Next, take spoonfuls of the cookie dough and drop them on top of the brownie layer. You can use a cookie scoop or just a tablespoon. Don’t worry about covering the brownie layer completely; it’s okay if some brownie peeks through!
12. Using a spatula or the back of a spoon, gently spread the cookie dough to create an even layer on top of the brownie batter. Again, it doesn’t have to be perfect; the layers will meld together while baking.
13. Place the assembled brookies in the preheated oven and bake for 25-30 minutes. Keep an eye on them; you want the edges to be set while the center remains slightly soft.
14. To check for doneness, insert a toothpick into the center. If it comes out with a few moist crumbs (not wet batter), they’re ready! If it comes out clean, they may be overbaked.
15. Remove the brookies from the oven and transfer them to a wire rack to cool completely before slicing into squares.

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