Preheat oven to 350°. Line a large baking sheet with parchment paper and set aside.
In a bowl of stand mixer or handheld mixer, cream together butter, granulated sugar and brown sugar.
Add egg, vanilla and peanut butter. Mix until smooth.
Add flour, baking soda and baking powder. Mix until well combined and smooth.
Using a spatula, carefully fold in fluff. You want to fold it in until its evenly distributed, but dont want to over fold. You want to make sure you have thick swirls!
Using a 1 1/2 tablespoon sized scoop, or using a heaping tablespoon sized scoop, scoop dough and place on lined baking sheet. I used an ice cream/cookie scoop, so I didnt have to roll them out in balls.
Bake in preheated oven for 8-10 minutes. The cookies will still be soft, but you want them to be! They will set perfectly while cooling off.
Enjoy!
