Preheat your oven to 350°F (175°C). This ensures that the brownie layers bake evenly, leading to that perfect texture we all crave.

Grease a 9x9-inch baking pan or line it with parchment paper. This allows for easy removal once the brownies cool. Trust me; you don’t want to be wrestling with your brownies!

In a large bowl, combine the brownie mix with 1/2 cup softened butter, 1 egg, and the required amount of water as per the package. Stir until fully mixed, ensuring no dry patches remain. This will form a thick, chocolatey batter.

Pour the brownie mix into the prepared baking dish. Using a spatula, spread it to cover the entire bottom evenly. It’s going to create a rich base for your cookie layer.

In another bowl, combine 3/4 cup granulated sugar, 2 tablespoons brown sugar, and 1/2 cup softened butter. Mix until creamy. Now, add the egg, vanilla, and espresso powder. Stir until well blended.

In a separate bowl, mix together the flour, baking soda, and salt. Gradually add these dry ingredients to the wet mixture, stirring just until combined. Don’t overmix; we want those cookie chunks to stay nice and thick!

Gently fold in the semisweet chocolate chips. If you’re feeling adventurous, go ahead and add walnuts or any other mix-ins you like!

Using a spoon or your hands (it’s fun!), drop spoonfuls of the cookie dough mixture on top of the brownie layer. You want to create an even distribution, but don’t stress about perfection. The swirls and gaps will create a lovely texture once baked.

Place the pan in the preheated oven and bake for about 30-35 minutes. Keep an eye out for the edges to firm up while the middle remains soft. A toothpick inserted into the brownie part should come out with a few moist crumbs.

Let the brownies cool in the pan for at least ten minutes before removing them. If you've used parchment paper, this should be a breeze! Slice into squares and serve