Line the pan with parchment paper and butter the parchment paper.
In a saucepan, over medium heat, add the butter, granulated sugar, and light brown sugar. Stir until the butter is all melted and combined with the sugars.
Set aside to cool for 4 to 5 minutes
In a large mixing bowl, mix the flour, cacao powder, salt, and chocolate chips. Mix until all ingredients are combined and the chocolate chips are coated with the flour mixture. Set aside.
To the butter-sugar mixture, once it has cooled, add the vanilla extract and the eggs one at a time. Mix well in between each.
Pour the butter-sugar mixture over the flour mixture. Mix until all ingredients are combined, no more dry flour.
Pour the mixture into the prepared 9x9 cake pan. Spread evenly. Set aside.
In a medium size bowl, mix the peanut butter, melted butter, powdered sugar, and vanilla extract.
Mix until all are combined.
Using a spoon, scoop the peanut butter onto the brownies.
Gently spread evenly with an offset spatula or butter knife.
Use a knife and make a swirl in the mixture.
Bake in the preheated oven for 30 to 35 minutes or until the edges are set.
Let the brownies cool off in the pan for 5 minutes.
Gently release the sides of the brownies and pull on the parchment paper.
Place on a cooling rack and let it cool for at least 1 to 2 hours.
Notes
Storage: Keep the brownies in an airtight container on the counter for 3-4 days and in the fridge for up to 1 week. Peanut Butter Brownies can be frozen for up to 3 months.
This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.