Go Back
+ servings
5 from 4 votes

Monster Cookies

Soft, chocolatey, chewy, and peanut buttery monster cookies. A family classic that we have been enjoying for decades.
Author Diana
Servings 32 small cookies
Prep Time 10 minutes
Cook Time 10 minutes
Total Time 20 minutes


  • ½ cup unsalted butter at room temperature
  • ½ cup light or dark brown sugar lightly packed
  • ¼ cup granulated sugar
  • 1 egg at room temperature
  • cup creamy peanut butter (not natural-style)
  • 1 teaspoon pure vanilla extract
  • 1 and ¼ all-purpose flour
  • ½ teaspoon baking soda
  • ½ cup old-fashioned whole rolled oats
  • ½ cup M&Ms*
  • ½ cup  semi-sweet chocolate chips optional


  • Using a hand mixer or a stand mixer fitted with a paddle attachment, cream the sugars with the butter on medium speed (it will take around 2 minutes). Then at high speed, mix in the egg, the peanut butter, and the vanilla extract (about 2 minutes). Set aside.
  • Add the flour and the baking soda, and mix on low speed until just combined. Fold in the oats, the M&M's, and chocolate chips.
  • Preheat oven to 400°F (200°C) and line two large baking sheets with parchment paper or silicone baking mats. Set aside.
  • Using a medium cookie scoop, scoop out the batter and place on baking sheets. Keep about 2 inches between the cookies as they will spread.
  • Bake for 8-10 minutes. The cookies will look soft and slightly under-baked. Remove them from the oven and allow them to cool down for 5 minutes.
  • Transfer to a wire rack to completely cool down.


  • This recipe makes 32 small cookies, or 16 regular cookies.
  • I recommend using mini M&Ms so you get more of them in each bite, but regular M&Ms work in this recipe too. If you only have larger M&Ms, such as peanut M&Ms or peanut butter M&Ms, I recommend chopping them into smaller pieces.
  • Use an electric beater to cream the butter with the sugar.
  • The butter MUST be softened to room temperature, and the egg must be at room temperature as well. Remember that butter at room temperature is imperative in the creaming butter with sugar step.
  • Feel free to add butterscotch morsels, white chocolate chips, or peanut butter chips to the cookie dough.
  • Peanut butter can be substituted with Sun Butter (sunflower butter) for a nut-free alternative.
  • Use a cookie scoop to create the cookie balls, it's easier and your cookies will be the same size.
  • The cookies can be kept in a sealed container at room temperature for up to 5 days, in the fridge for up to 7 days, or in the freezer for up to 2 months.


Calories: 116kcal | Carbohydrates: 11g | Protein: 2g | Fat: 8g | Saturated Fat: 4g | Cholesterol: 13mg | Sodium: 48mg | Potassium: 62mg | Fiber: 1g | Sugar: 8g | Vitamin A: 103IU | Calcium: 13mg | Iron: 1mg