Ingredients:

• 1 cup (2 sticks) unsalted butter, melted
• 1 cup granulated sugar
• 1 cup packed brown sugar
• 4 large eggs
• 2 teaspoons vanilla extract
• 1 cup all-purpose flour
• 1 cup unsweetened cocoa powder
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 1 cup semi-sweet chocolate chips
• 1 cup chopped nuts (optional)
• 1 cup all-purpose flour (for the cookie dough layer)
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 1/2 cup (1 stick) unsalted butter, softened
• 1/2 cup granulated sugar
• 1/2 cup packed brown sugar
• 1 large egg
• 1 teaspoon vanilla extract
• 1 cup semi-sweet chocolate chips (for the cookie dough layer)

Preparing the Brownie Batter

Let’s start by making the brownie base, which is rich and fudgy. Follow these steps:

1. Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking pan or line it with parchment paper for easy removal later.
2. In a large mixing bowl, combine the melted butter, granulated sugar, and brown sugar. Whisk them together until the mixture is smooth and well combined.
3. Add the eggs, one at a time, mixing well after each addition. Then stir in the vanilla extract until everything is nicely blended.
4. In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt. This step is crucial as it helps to aerate the dry ingredients and ensures there are no lumps.
5. Gradually add the dry ingredients to the wet mixture, stirring gently until just combined. Be careful not to overmix; we want our brownies to be fudgy!
6. Fold in the chocolate chips and nuts (if using) until evenly distributed throughout the batter.

Baking the Brownie Layer

Now that we have our brownie batter ready, it’s time to bake it:

1. Pour the brownie batter into the prepared baking pan, spreading it evenly with a spatula.
2. Bake in the preheated oven for about 25-30 minutes. You’ll know they’re done when a toothpick inserted into the center comes out with a few moist crumbs, but not wet batter.
3. Once baked, remove the brownies from the oven and let them cool in the pan on a wire rack while we prepare the cookie dough layer.

Preparing the Cookie Dough Layer

While the brownies are cooling, let’s whip up the cookie dough that will sit on top:

1. In a medium bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy. This should take about 2-3 minutes.
2. Add the egg and vanilla extract, mixing until well combined.
3. In another bowl, whisk together the flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, stirring until just combined.
4. Fold in the chocolate chips until they are evenly distributed throughout the cookie dough.

Assembling the Cookie Brownies

Now comes the fun part—layering the cookie dough on top of the brownies:

1. Once the brownie layer has cooled completely, take spoonfuls of the cookie dough and drop them evenly over the brownie layer. You can use your hands to gently spread the cookie dough, but it’s okay if some brownie peeks through.
2. Make sure to cover the brownie layer as evenly as possible, but don’t worry about making it perfect. The cookie dough will spread while baking.
3. Return the assembled pan to the oven and bake for an additional 20-25 minutes, or until the cookie dough is golden brown and set in