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You’ll want to try this no-fail monster cookie recipe for your next get together. They are chewy, crunchy, and hard to eat just one!

We love this monster cookie recipe because they’re basically a combination of Oatmeal Cookies, Peanut Butter Cookies, and M&M Cookies! Just doesn’t get better than that.

Stack of Monster Cookies served on a plate.
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These monster cookies are the BEST!

My kids are constantly requesting this cookie recipe. I love to make them for so many occasions – birthdays, dinner parties, potlucks, church gatherings, picnics, or just a yummy after-school treat.

I love the color from the M&Ms and the chewiness from the oatmeal. If you’ve never made monster cookies before, TRUST ME, they are amazing.

These will definitely become your new favorite cookie and you won’t be able to live without this recipe. Plus – they’re easy to change up with all the different varieties of M&Ms!

M&Ms in glass bowl.

How to Make Them

This monster cookie recipe is packed with chocolate and absolutely delicious!

PREP. Prepare a cookie sheet by lining it with parchment paper or using cooking spray. Make sure the oven is preheated to 350°F.

DOUGH. Use a hand mixer or stand mixer to combine the peanut butter, sugars, and butter. Mix these together and then add the eggs and vanilla. Next, mix in the quick oats and baking soda. Finally, stir in the chocolate chips and M&M’s.

BAKE. Use a cookie scoop for regular size or an ice cream scoop for giant cookies. Drop the cookie dough onto the baking sheet. (To make them picture perfect add a few chocolate chips and M&Ms to the top of the scoops. I love this trick!)

  • Cookie Scoops: Bake for 10 to 12 minutes.
  • Ice Cream Scoops: Bake for 18-20 minutes. Be sure you do not overbake!!

Allow the cookies to cool for a few minutes before transferring them to a wire rack to finish cooling off.

Altitude. I don’t live at high altitude so I couldn’t test it, but I read that one baker uses an extra egg to help her monster cookies come out perfect.

Chocolate chips and M&Ms added to cookie batter.

This best monster cookie recipe could be filled with even more chewy mix-ins!

Shape. I did not find that these cookies spread very much. Once the dough is on the cookie sheet lightly press the dough with the palm of your hand to give them shape. This is especially helpful if you choose to make larger cookies. 

If your cookies are spreading too much double-check that you are using enough oatmeal and the butter is room temperature and cool to the touch. You can also chill the dough for 20-30 minutes before baking.

Prep the pan. Be sure to spray the cookie sheet, line it with parchment paper, or use a silpat mat.

Other mix-ins. We like using chocolate chips and plain M&M’s, but you can use your favorite mix-ins such as raisins, craisins, white chocolate or butterscotch chips, Reese’s Pieces, or mini M&M candies. 

Be cautious to not add too many mix-ins otherwise, there will not be enough dough to hold it all together.

Cookie dough balls on a cookie sheet.

Storing Info

Store the dough. Cover the bowl of dough and keep it in the fridge for 1-2 days. For longer storage flash freeze the balls of dough and store them in a Ziploc bag in the freezer for 1-2 months. Thaw for 20-30 minutes before baking them. 

Store baked cookies.  Allow the cookies to cool completely before storing them. Keep in an airtight container for 1 week. Place a piece of white bread in the container to help keep them soft and fresh. These Monster Cookies can also be stored in the freezer for up to 6 months. 

Close up of our famous monster cookie recipe served on a plate.

Recipe FAQ

Can I make monster cookies using natural peanut butter?

The peanut butter is the “glue” that holds these cookies together. For the best result use regular peanut butter such as Jif or Skippy. You can try almond butter or natural peanut butter, but the result may be a dry crumbly cookie. You can also use regular crunchy peanut butter for a bit of texture.

What oats do I use to make monster cookies?

I used quick oats because I like the texture and structure that it creates within the cookie. You can use regular oats if that is what you have on hand but do not use steel-cut oats or instant oats.

Are oatmeal monster cookies gluten-free?

These cookies are made without using flour. However, you need to check the other ingredients, like the oats, to be sure they do not contain hidden gluten.

5 from 37 votes

Monster Cookie Recipe

By: Lil’ Luna
Bake up a batch of these monster cookies for any occasion. They are chewy, crunchy, and hard to eat just one!
Servings: 36
Prep: 15 minutes
Cook: 10 minutes
Total: 25 minutes

Ingredients 

  • cups creamy peanut butter or chunky
  • 1 cup brown sugar packed
  • 1 cup sugar
  • ½ cup unsalted butter room temperature
  • 3 large eggs
  • 1 tablespoon vanilla extract
  • cups quick cooking oats
  • 2 teaspoons baking soda
  • 1 cup milk chocolate chips
  • 1 cup plain M&Ms

Instructions 

  • Prepare a cookie sheet by lining it with parchment paper or using cooking spray. Preheat the Oven to 350°F.
  • Use an electric mixer to combine peanut butter, sugars, and butter. Mix well then add the eggs and vanilla. Next, mix in the quick oats and baking soda. Finally, stir in the chocolate chips and M&M's.
  • Use a cookie or ice cream scoop to drop the dough onto the baking pan. (To make them picture perfect add a few chocolate chips and M&Ms to the top of the scoops.)
  • Cookie scoops: Bake for 10 to 12 minutes. Ice Cream Scoops: bake for 18-20 minutes. Be sure you do not overbake!!
  • Allow the cookies to cool for a few minutes before transferring them to a wire rack to finish cooling off.

Video

Notes

NOTE: This recipe does not use flour, but other items may include gluten. Please read the labels if you want to be sure.

Nutrition

Calories: 228kcal, Carbohydrates: 28g, Protein: 5g, Fat: 12g, Saturated Fat: 5g, Cholesterol: 22mg, Sodium: 125mg, Potassium: 119mg, Fiber: 2g, Sugar: 19g, Vitamin A: 123IU, Vitamin C: 1mg, Calcium: 30mg, Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

About Kristyn

My name is Kristyn and I’m the mom of SIX stinkin’ cute kids and the wife to my smokin’ hot hubby, Lo. My mom’s maiden name is Luna, and I’m one of the many crafty “Lil’ Lunas” in the fam. On this site I like to share all things creative - from recipes to home decor to gifts and home decor ideas. Welcome!

So Easy & So Yummy

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5 from 37 votes (23 ratings without comment)

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Recipe Rating




22 Comments

  1. Alissa C says:

    5 stars
    These are the COOKIES! they are the perfect blend of sweet and nutty, with a little oatmeal sturdiness mixed in. We love them!

  2. Erica Barlow says:

    5 stars
    Love these yummy M&m cookies! We love to make them with the seasonal m&ms 😁

  3. G says:

    5 stars
    High altiTUde ADJUSTMENT (7,000 ft). Added an extra egg as noted, decreased both suGars by about 1/2 as much. Baked for 8 min. So good!! Cooked bUt still chewy inside!

    1. Kristyn Merkley says:

      Thank you so much for sharing that!! Hopefully, that helps those who need it 🙂

  4. Olivia says:

    5 stars
    a little bit of everything In it cookie. A fun little cookie to make and eat!

  5. Kristi says:

    5 stars
    Everything good abouT cookies all in one! These are so amazing.

  6. Kara says:

    5 stars
    My entire family loves these cookies! I sometimes toss in some semi sweet or peanut butter chips to change things up a bit, and they are always amazing. I like to double the batch and keep extras in the freezer for quick treats. 🙂

  7. Rachael Yerkes says:

    5 stars
    THESE ARE A FAVORITE FOR MY KIDS! THEY LOOK FUN, TASTE GOOD, AND ARE EASY ENOUGH TO MAKE THAT THE KIDS HAVE A FUN TIME TOO!

  8. trang says:

    5 stars
    YUMMY! DEFINITELY APPROVED BY MY KID AND ESPECIALLY BY ME. I LOVE CHOCOLATE CHIP COOKIES BUT ADDING M&M’S MAKES IT SO MUCH BETTER!

  9. Joy says:

    5 stars
    Love that these have a little bit of everything! They really are so good! I love the combination!

  10. Alissa says:

    5 stars
    Delicious Cookies. We loved them, even with the crunchy peanut butter we had on hand. I usually prefer a hot, warm cookie, but these were even better the 2nd day. Yum! I can imagine, with your tips, how well these would freeze. Thanks for all those details. For real, your notes on all your recipes are the best!

    1. Kristyn Merkley says:

      Awe, that’s so nice of you to say that! Thank you for letting me know!