Preheat the oven to 175ºC conventional oven. Prep a 20x20 cm square pan with parchment paper.
In a bowl add the butter, peanut butter, brown sugar and granulated sugar, and with an electric hand mixer, whisk it together for 1-2 min.
35 g butter, 30 g smooth peanut butter, 40 g brown sugar, 70 g granulated sugar
Add the egg and mix it in. Then add the vanilla extract and mix it in.
1 large egg, 1 teaspoon vanilla extract
In a separate bowl, stir together all-purpose flour, baking powder, and salt. Then add it into the butter sugar mixture. With a rubber spatula, fold it together until just combined.
125 g all-purpose flour, ¼ teaspoon baking powder, ¼ teaspoon salt
Add ¾ off the cookie dough to the bottom of the baking pan and even it out. Set it aside while making the brownie batter.
BROWNIE
Melt the butter and chocolate over a double boiler or in the microwave.
125 g butter, 125 g dark chocolate chips
In a bowl, mix together the eggs, brown sugar and granulated sugar until light and fluffy, about 1 minute.
125 g brown sugar, 100 g granulated sugar, 2 eggs
While mixing, in a steady stream pour the melted butter and chocolate into the batter and mix until combined. Then add the vanilla extract and whisk it until combined.
1 teaspoon vanilla extract
With a rubber spatula fold in the all-purpose flour, cocoa powder and salt into the batter and gently fold it together until combined.
150 g all-purpose flour, 2 tablespoon cocoa powder, ¼ teaspoon salt
Pour the batter over the cookie dough and smooth it out with the spatula.
PEANUT BUTTER FILLING
Mix together the smooth peanut butter and powdered sugar until combined. Divide the peanut butter filling and the remaining cookie dough on top of the brownie batter and sprinkle with peanuts.
80 g smooth peanut butter, 40 g powdered sugar, Small handful of salted peanuts
Bake for about 30-35 min. It shouldn’t jiggle when taken out of the oven but when using a cake tester, moist crumbs should be one it. Let it cool down completely until cold and it’s ready to be enjoyed