Preheat your oven to 350°F (175°C). Line a 9x9-inch baking dish with parchment paper or lightly grease it to ensure the brownies come out easily.
In a large mixing bowl, beat together the softened 1/3 cup unsalted butter, 2/3 cup peanut butter, and 2/3 cup brown sugar until smooth and creamy, about 2-3 minutes. Add in the 1 tsp vanilla extract and mix until well combined.
1 tsp vanilla extract, 2/3 cup peanut butter, 2/3 cup brown sugar, 1/3 cup unsalted butter
In a separate bowl, whisk together the 1 cup all-purpose flour and 1/4 tsp baking powder. Gradually add the dry ingredients to the wet mixture, mixing until the dough comes together.
1/4 tsp baking powder, 1 cup all-purpose flour
Press about two-thirds of the cookie dough evenly into the bottom of the prepared baking dish to form the crust. Set aside the remaining dough for the crumble topping.
In a large mixing bowl, combine the 1 1/2 cups granulated sugar, 3/4 cup all-purpose flour, 2/3 cup cocoa powder, and 1/2 cup powdered sugar. Stir until well combined. Add in the 2 large eggs, 1/2 cup vegetable oil, 2 tbsp hot water, and 1 tsp vanilla extract. Mix until the batter is smooth.
1 1/2 cups granulated sugar, 3/4 cup all-purpose flour, 2/3 cup cocoa powder, 1/2 cup powdered sugar, 2 large eggs, 1/2 cup vegetable oil, 2 tbsp hot water, 1 tsp vanilla extract
Pour the brownie batter evenly over the peanut butter cookie crust.
Drop spoonfuls of the 1/2 cup peanut butter over the brownie batter and use a knife or skewer to swirl the peanut butter into the brownie layer. This will create a beautiful marbled effect.
1/2 cup peanut butter
Take the remaining peanut butter cookie dough and crumble it over the top of the brownie layer. You want the crumble to be in small pieces, so use your fingers to scatter it evenly across the top of the brownies.
Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs (not wet batter). The edges should be set, but the center will still be slightly soft.
Let the brownies cool completely in the pan before cutting them into squares.
Once cooled, cut the brownies into squares and enjoy the rich, fudgy texture of the brownies paired with the soft peanut butter cookie crust and crumbles. These are perfect for any occasion—whether you’re indulging yourself or sharing with friends!