Preheat the oven to 350 F. Line a 12-cup muffin pan with paper liners. In a medium bowl, whisk together flour, quick oats, salt, and baking soda. In a large bowl, combine softened butter with peanut butter, and both sugars. Mix until fluffy.
Add in the egg and vanilla extract, and mix until smooth. Add in the flour mixture, and mix until fully combined. Evenly divide the cookie dough into the paper liners. Bake for 15-20 minutes.