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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. Spread the brownie batter evenly in the bottom of the prepared baking pan. Use a spatula to smooth it out if needed.
11. Take spoonfuls of the cookie dough and drop them over the brownie layer. You can use your hands to flatten the cookie dough slightly if you prefer a more even layer.
12. Use a spatula to gently spread the cookie dough out, covering as much of the brownie layer as possible. It’s okay if some brownie peeks through.
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. Once baked, remove the pan from the oven and let it cool in the pan for about 10-15 minutes.
15. Cut them into squares while still in the pan. Enjoy your delicious brookies warm or at room temperature!

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