Preheat the oven to 350 F. Line the bottom of an 8x8 pan with parchment paper. I just cut out a square of parchment paper and press it in the bottom. Then spray the pan with non-stick spray.
Melt the butter until it's liquid and add it to a large mixing bowl. Mix in the cocoa powder until it's fully incorporated. Then add the sugar and mix until completely blended in. Whisk the eggs in until fully incorporated.
Add the baking powder and salt. Add the flour. I like to add the flour in three batches. This helps it mix in better and prevents it from getting all over everything.
Next, fold in the chocolate chips and peanut butter chips. Pour the batter into the prepared pan.
Add the peanut butter to a glass measuring cup and melt it in the microwave for about 20 seconds. You don't want it to be too runny, but you do want to be able to pour it out.
Pour the peanut butter over the batter in the pan. I like to make a square then make lines crisscrossing each other. You can make any pattern you want to though. Drag a knife lightly through the peanut butter to create a rough design. It doesn't have to be perfect. You don't want to fully incorporate the peanut butter, but mixing it a bit with the chocolate can create a cool look.
Once you finish with that, pop it in the oven for 28 minutes. A toothpick inserted in the middle should have moist crumbs on it and the center will be a bit jiggly. If you want a bit of a gooey center, bake it for 25 minutes.
Let the brownies fully cool down before slicing into them. I know it's hard to wait, but this step is important as it allows the brownies to set up properly. To release them from the pan, slide a knife around the edge of the brownie and the pan all the way around. Turn it over onto a paper towel and it should release easily. Lay on a cooling rack to cool it down fully. If you want to speed up the process, pop it in the fridge for 30 minutes. This makes handling it a bit easier.
Enjoy either alone or with ice cream. And maybe a caramel drizzle. Share if you feel like it.