Gather your ingredients. In a medium mixing bowl, combine the flour, baking soda, and baking powder.
Using a stand mixer or hand mixer, beat together the butter, brown sugar, and granulated sugar. Beat the mixture until smooth. Next, add in the peanut butter and egg and beat to combine.
With the mixer set to the slowest speed, slowly add in the flour mixture and continue beating until it's well combined.
Line a baking sheet with parchment paper. Shape the cookies into a ball and flatten each ball slightly with your palms. Using a fork, create a criss-cross pattern on top of the cookies.
Bake the cookies at 350°F for 10 minutes. Remove the cookies from the oven and allow them to cool for at least 5 minutes. They may look a little underbaked, but don't worry - they will harden as they cool. Enjoy!