Preheat the oven to 350.

Beat the butter and sugar together using a hand mixer or stand mixer at medium speed until light and fluffy, about 1-2 minutes. Add the egg and vanilla and beat until well combined. Add the peanut butter and beat again until well combined.

In a separate small bowl, combine the quick oats, baking soda, cinnamon and salt. Stir well to combine.

Add the dry ingredients to the bowl with the wet ingredients and mix together by hand until well combined. The mixture will be wet and sticky.

Scoop the batter onto an ungreased baking sheet, using about 1 ½ tablespoons per cookie. (You’ll need two baking sheets, each with 10 cookies, to make the entire batch.) Wet your fingers if needed to help transfer the batter without it sticking to you.

Bake at 350 for 10 minutes, until the cookies are brown around the edges and set in the middle.

Let sit on the baking sheets for a few minutes to cool slightly before moving. (They’ll be soft and crumbly right out of the oven but they set up as they cool, so don’t move them too quickly.)

Store, covered, at room temperature for up to a week.