
Preheat the oven to 350°F and line two baking sheets with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment, add the butter and sugars. Cream together on medium-low speed until light and fluffy, about 2–3 minutes. Add the peanut butter and continue mixing to combine. Then, add the egg and vanilla extract and mix on low speed until incorporated, about 1 minute.
In a separate bowl, whisk together the flour, baking soda, and salt. Add the dry ingredients to the wet ingredients and mix until just combined. Add the oats and mix until just incorporated.
Using a 1.5 tablespoon spring-loaded cookie scoop, scoop a rounded amount of dough and place 2 inches apart on the prepared baking sheet. Lightly flatten the top of each cookie with your fingers.
Bake for 10–12 minutes, or until the edges are just set and lightly golden.
Remove from the oven and allow to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.