Preheat oven to 350°F. Grease an 8x8 pan and line with parchment paper, if desired. Set aside.
In a large bowl, combine the flour, cocoa powder and salt. Set aside.
In a separate bowl, combine butter and peanut butter. Microwave in 25 second increments, until the butter is completely melted. Add in the remaining brownie ingredients, and whisk for about a minute until everything is smooth and combined.
Pour the butter mixture into the flour, and whisk together until the brownie batter is smooth. Pour finished batter into the prepared pan.
In a small bowl, add the 2-3 tablespoons of peanut butter and microwave for about 15 seconds to slightly melt it. Drop small spoonfuls of peanut butter all over the top of the brownie batter. Using a toothpick or butter knife, drag it lightly along the top of the brownies, through the peanut butter. You can do this a few times, change direction, etc. to get the swirl pattern you like.
Pop in the preheated oven and bake for 40-42 minutes. It may take up to 45 minutes, depending on your oven. Enjoy!