Monster cookies with m&m's on a wire cooling rack.
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5 from 1 vote

Thick and Chewy Monster Cookies

Thick and chewy Monster Cookies made with oats, peanut butter, M&M candies and chocolate chips. These are always a huge hit with family and friends.
Prep Time15 mins
Cook Time10 mins
Total Time25 mins
Course: Dessert
Cuisine: American
Servings: 24
Calories: 191kcal
Author: Lauren Allen


  • 1/2 cup butter
  • 1/2 cup granulated sugar
  • 1/2 cup light brown sugar
  • 1/2 cup peanut butter
  • 1 egg
  • 1 teaspoon vanilla extract
  • 1 cup all-purpose flour
  • 1 1/4 cups old-fashioned rolled oats
  • 1/4 teaspoon salt
  • 1/2 teaspoon baking powder
  • 1/2 teaspoon baking soda
  • 3/4 cup M&M candies
  • 1/2 cup semi-sweet chocolate chips


  • Preheat oven to 350 degrees F.
  • Cream the butter and sugar together really well—at least 2-3 minutes until light and fluffy.
  • Add peanut butter and mix well. Add egg and vanilla and mix.
  • In a separate mixing bowl stir together the flour, oats, salt, baking powder and baking soda.  (Be extra careful not to add too much flour).
  • Add to the wet mixture and mix to combine. Stir in chocolate chips and M&M’s.
  • Bake at 350 degrees for 10-12 minutes, or a little longer if you make them bigger than a 1 inch cookie scoop. Don't over bake--they will look just set. 
  • Remove them from the oven and allow them to cool completely on the pan.



Adapted from our Mrs. Fields chocolate chip cookie recipe.


Calories: 191kcal | Carbohydrates: 23g | Protein: 3g | Fat: 9g | Saturated Fat: 4g | Cholesterol: 18mg | Sodium: 114mg | Potassium: 94mg | Fiber: 1g | Sugar: 14g | Vitamin A: 145IU | Calcium: 25mg | Iron: 0.9mg