Preheat oven to 375℉ (190℃)
Prepare two baking sheets by lining with parchment paper or silicone baking mats.
In a medium bowl, whisk together flour, baking soda, and baking powder. Set aside for later.
1 ½ cup All-purpose flour, ¾ teaspoon Baking soda, ½ teaspoon Baking powder
Using a stand mixer fitted with the paddle attachment, mix the butter, brown sugar, and granulated sugar on medium speed until light and fluffy, about 2–4 minutes. Scrape down sides of bowl as needed. Note: A hand mixer can also be used for this step.
½ cup Unsalted Butter, ½ cup Granulated Sugar, ½ cup Light Brown Sugar
Add peanut butter to the mixing bowl. Mix on medium speed until well combined. Scrape down sides of bowl as needed.
¾ cup Creamy peanut butter
Add the egg and mix on medium speed until fully incorporated. Scrape down the sides of the bowl as needed.
1 large Egg
Add flour mixture and mix on low speed until combined.