Peanut Butter Oatmeal Cookies

These cookies have a rich, peanut buttery, nutty oat flavor, with crisp edges and a melt in your mouth chewy center. I even added some Reese's Pieces to half the batch for an extra special addition!

To start, simply sift the dry ingredients and set aside. Then beat together the butter, PB and sugars.

Add the wet ingredients.

After you have weighed or measure out your flour, slowly mix it in.

Add the oats.

Scoop onto baking sheet. Feel free to add any toppings you desire, I like to add Reese's Pieces for an extra peanut buttery touch, but anything from chocolate chips to raisins to M&Ms will work! 

Make sure not to over bake, so the cookies don't come out hard and crumbly! Enjoy warm and fresh out of the oven, or let cool completely.

Peanut Butter Oatmeal Cookies {Small Batch}

Yield: 16 cookies*
*For a small batch, cut the recipe below in half, using 1 large egg yolk plus 1 1/2 teaspoons milk for half of an egg.

  • 3/4 cup (90g) all-purpose flour, weighed or spooned and leveled
  • 1/2 teaspoon baking soda 
  • 1/4 teaspoon salt 
  • 2 teaspoons ground cinnamon
  • 1/2 cup (1 stick) unsalted butter, melted (browned if desired)
  • 1/2 cup creamy peanut butter
  • 3/4 cup packed brown sugar 
  • 1/4 cup granulated white sugar 
  • 1 large egg
  • 1 teaspoon pure vanilla extract 
  • 3/4 cup quick cooking oats
  • 1 cup Reese's Pieces, chocolate chips, or mix-ins of your choice, optional 


Preheat oven to 350 degrees F.

Sift together the flour, baking soda, salt and cinnamon; set aside. With an electric mixer, beat together melted butter, peanut butter and sugars on medium speed for a minute or two. On low speed, add the egg, milk and vanilla extract. Gradually add the flour mixture just until incorporated. Fold in the oats, followed by the mix-ins of your choice with a spatula or wooden spoon. Scoop dough (about 2 tablespoons each) onto parchment lined cookie sheet. 

Bake 11-13 minutes or until edges just start to turn golden brown but centers are still soft and puffy. Do not over bake. Let cookies cool for about 2 minutes on baking sheet before transferring them to a wire rack.