Creating The Best Fudgy Chewy Brownies (Brookies) can be simple if you follow these easy steps:

1. Preheat your oven to 350°F (175°C). Grease and line a 9×13-inch baking pan with parchment paper, leaving some overhang for easy removal.
2. Prepare the Brownie Mixture: In a medium saucepan, melt the unsalted butter over low heat. Once melted, remove from heat and stir in the granulated sugar. Allow it to cool slightly.
3. Add Eggs and Vanilla: Stir in the eggs, one at a time, mixing well after each addition. Finally, add the vanilla extract and mix until well combined.
4. Combine Dry Ingredients: In a large bowl, whisk together the flour, cocoa powder, salt, and baking powder. Gradually add the dry ingredients to the wet mixture, stirring until just combined. Fold in the chocolate chips for the brownie layer.
5. Prepare the Cookie Mixture: In another mixing bowl, cream together the brown sugar, granulated sugar, and softened butter until light and fluffy.
6. Add Eggs and Vanilla: Add the eggs and vanilla extract, mixing well until fully incorporated.
7. Combine Dry Ingredients: In a separate bowl, mix the flour, baking soda, and salt. Gradually add this to the wet mixture, stirring until combined. Fold in the chocolate chips and optional nuts if desired.
8. Layer the Mixtures: Spread the brownie batter evenly into the prepared baking pan. Layer the cookie dough over the brownie batter, gently pressing it down.
9. Bake: Place the pan in the preheated oven and bake for 25-30 minutes. The edges should look set, while the center will still be slightly soft.
10. Cool: Remove from the oven and let cool in the pan for about 10-15 minutes. Use the parchment overhang to lift the brownies out of the pan. Allow them to cool completely on a wire rack before slicing.

These steps will guide you in creating The Best Fudgy Chewy Brownies (Brookies) that are sure to impress.