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These monster cookies are thick, soft and chewy loaded with oats, peanut butter, M&Ms and chocolate chips. They are a family favorite and you don’t have to chill the cookie dough!

Homemade cookie recipes are always a hit with friends and family and this one is the best combination of peanut butter M&M cookie and oatmeal cookie!

Monster cookies with chocolate and m&ms.
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Best Monster Cookies

I’ve tested a lot of monster cookies over the years and this recipe from my friend Maria’s Two Peas & Their Pod Cookbook is perfectly soft and chewy, with a thick texture. Plus, they’re loaded with chocolate chips and M&M’s. Double the chocolate, right?!

This recipe is like eating all the best cookies in one delicious bite! Part peanut butter cookie, part chocolate chip cookie and part M&M cookie all in one. If you love the combination of peanut butter, oatmeal and M&M’s, these bake up soft, chewy plus are monstrous in size!

How to Make Monster Cookies

Mixing monster cookie dough in glass bowl with wooden spoon.
  1. Cream ingredients. In the large bowl of a mixer, beat butter and sugars until creamy. Then add in peanut butter and beat for an additional minute. Stir in the eggs and vanilla and mix until well combined.
  2. Add remaining ingredients. Whisk together oats, flour, baking soda and salt in a medium-sized bowl. Slowly stir in the oat mixture with wet ingredients and mix just until combined. Fold in the chocolate chips and M&M’s, reserving some for tops. If desired, add in pretzel pieces.
  3. Scoop. Using a large cookie scoop, scoop dough onto a lined baking sheet (about 2 inches apart). Then press down lightly on the dough balls with the palm of your hand. Add the reserved M&M’s and/or chocolate chips to the tops.
  4. Bake. Bake at 350°F until the edges are lightly browned, about 10-11 minutes. Let sit on baking sheet for about 3-5 minutes, then transfer to cooling rack. Repeat with the remaining dough. Enjoy!
Bowl full of monster cookies.

Baking Tips and Tricks

  • Make sure to use old fashioned rolled oats – they give the cookies that perfect chewy texture.
  • Use regular creamy peanut butter, not the natural or crunchy kind. I like to use Jiff or Skippy.
  • Add additional M&M’s and chocolate chips on top of cookie dough balls before baking.
  • Use holiday M&M’s to make the cookies more festive.
  • Add in chopped pretzels for a sweet and salty combo. I like to add some on top too.
  • They should look a little underdone in middle when removing from oven (they’ll continue baking on pan).
  • Add a sprinkle of maldon salt on top of the cooked cookies to boost the flavor even more.

Storing + Freezing

  • Storage: Store at room temperature in an airtight container for up to 3 days.
  • Freezing: Place in a freezer bag or airtight container and freeze for up to 3 months. Let thaw in fridge overnight or set on counter for a few hours until no longer frozen.
Monster cookies on pan.

Giant Monster Cookies

Turn into MEGA monster cookies by forming the dough into about 16 large round balls (1/3 cup of dough). Then bake an additional 2-3 minutes in the oven. This is how Maria suggests making them. I made a few of mine that way and they were just like you would pick up from the bakery. Super thick and delicious. However I find using a large cookie scoop is the perfect amount for my family.

Halloween Version

You could even turn these into true monster cookies by adding candy eyeballs (below). How cute are these?! Such a fun Halloween dessert that’s perfect to bring to parties. Both adults and kids love them!

Monster cookie with candy eye balls.

More Delicious Cookie Recipes

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monster cookies

Monster Cookies

5 from 14 votes
↑ Click stars to rate now!
Author: Jamielyn Nye
These monster cookies are thick, soft and chewy loaded with oats, peanut butter, M&Ms and chocolate chips. They are a family favorite and you don't have to chill the cookie dough!
Prep Time: 10 minutes
Cook Time: 10 minutes
Total Time: 20 minutes
Servings: 32

Ingredients 

  • 3 cups old-fashioned rolled oats
  • 1 ½ cups all-purpose flour
  • 1 teaspoon baking soda
  • 1 teaspoon Kosher salt
  • 1 cup unsalted butter (at room temperature)
  • 1 cup creamy peanut butter
  • 1 cup granulated sugar
  • 1 cup light brown sugar , packed
  • 2 large eggs
  • 2 teaspoons vanilla extract
  • 1 cup M&M's candies (reserve some for tops)
  • 1 cup semi sweet chocolate chips (reserve some for tops)
  • 1 cup chopped pretzels (optional)

Optional: Maldon sea salt flakes, for sprinkling

    Instructions

    • Preheat the oven to 350°F. Line a large baking sheet with parchment paper or a silicone baking mat and set aside.
    • In a medium bowl, whisk together the oats, flour, baking soda and salt. Set aside.
    • In a large bowl, beat together the butter and sugars until creamy. Then add the peanut butter and beat an additional minute. Add in the eggs and vanilla and mix until well combined. Slowly mix in the oat mixture and mix just until combined.
    • Stir in the M&M's and chocolate chips, reserving some for the tops if desired. Add the pretzels if desired.
    • Use a large cookie scoop to scoop dough onto prepared baking sheet, about 2 inches apart. Lightly press down on the dough balls with the palm of your hand. Add additional M&M's and/or chocolate chips to the tops.
    • Bake for 10-11 minutes, or until the edges are lightly browned. Allow cookies to sit on the baking sheet for 3-5 minutes and then transfer to a cooling rack. Repeat with the remaining dough.

    Notes

    Store in an airtight container at room temperature for up to 3 days or freeze up to 3 months.
    Note: To make mega monster cookies, form the dough into about 16 large round balls (1/3 cup of dough). Then bake an additional 2-3 minutes. 
    Recipe from The Two Peas and Their Pod Cookbook 

    Nutrition

    Serving: 1cookie | Calories: 270kcal | Carbohydrates: 32g | Protein: 5g | Fat: 14g | Saturated Fat: 7g | Cholesterol: 30mg | Sodium: 157mg | Potassium: 134mg | Fiber: 2g | Sugar: 20g | Vitamin A: 214IU | Vitamin C: 1mg | Calcium: 29mg | Iron: 1mg

    Nutrition provided is an estimate. It will vary based on specific ingredients used.

    Course: Dessert
    Cuisine: American

    Did you make this recipe? Don’t forget to give it a star rating below!

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