Go Back
Closeup of Monster Cookies laying on parchment paper topped with M&M's and chocolate chips
Print Pin
5 from 5 votes

Monster Cookies

 Get ready to sink your teeth into big, thick cookies packed full of chocolate, peanut butter, oats, and M&M's.
Course Cookies, Dessert
Cuisine Dessert
Prep Time 15 minutes
Cook Time 10 minutes
Total Time 25 minutes
Servings 15 large cookies
Calories 292kcal


  • ¾ cup all purpose flour
  • ¾ teaspoon baking soda
  • ¼ teaspoon salt
  • 1 cup old fashioned rolled oats
  • ½ cup unsalted butter softened but still cool
  • cup creamy peanut butter* at room temperature
  • ½ cup granulated sugar
  • ½ cup brown sugar, packed
  • 1 teaspoon pure vanilla extract
  • 1 large egg
  • 1 ½ cups combination of: chocolate chips, peanut butter chips, M&M's, and chopped honey roasted peanuts**
  • ¼ cup chocolate chips and/or M&M's for topping the cookies optional


  • Preheat oven to 350°F. Line two baking sheets with parchment paper.
  • In a large bowl, combine flour, baking soda, salt, and oats. Set aside.
  • In a large bowl, with a hand mixer or stand mixer fitted with the paddle attachment, beat butter and peanut butter until smooth. Add both sugars and beat until combined. Beat in egg and vanilla, scraping the sides of the bowl as needed. Add flour mixture and mix on low speed until thoroughly combined. Stir in 1-½ cups of mix-ins**.
  • Scoop the dough into generous ¼-cup balls (I use an ice cream scoop) and place the dough balls a couple inches apart on the prepared baking sheets. Flatten the dough mounds slightly. Using the remaining ¼ cup chocolate chips/M&M's press several onto the tops of each dough mound (this makes for a prettier cookie).
  • Bake for 10-13 minutes, rotating the baking sheets front-to-back/top-to-bottom once during bake time. Bake until the edges are just beginning to darken but the centers are still undercooked (the cookies should be so soft/underbaked that you can't pick them up yet). Place the baking sheets on wire racks to cool and firm up.



*I prefer an emulsified/no-stir peanut butter for this recipe because it produces the most consistent result. 
**I used ⅓ cup peanut butter chips, ⅓ cup chocolate chips, ⅓ cup chopped honey roasted peanuts, and ½ cup M&M's inside the cookie dough.


Calories: 292kcal | Carbohydrates: 33g | Protein: 5g | Fat: 17g | Saturated Fat: 8g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 5g | Trans Fat: 1g | Cholesterol: 33mg | Sodium: 159mg | Potassium: 117mg | Fiber: 1g | Sugar: 23g | Vitamin A: 207IU | Calcium: 19mg | Iron: 1mg