These Gluten-Free Monster Cookies are loaded with peanut butter, oats, and M&Ms. They have crispy edges and are soft and chewy.

It costs about $8.41 to make these cookies. The recipe makes twenty-four cookies which cost approximately $0.35 per cookie.

Adding M&Ms to cookies is such a fun treat! Try my Cake Mix Cookies, M&M Pretzel Cookies,  and Chocolate Chip Shortbread Cookies with M&Ms for more fun treats.

The finished recipe with text overlay for Pinterest.

Monster Cookies

I debated whether or not I should call these Monster Cookies “Gluten-Free.” While they are gluten-free, I don’t want their gluten-free label to dissuade anyone from trying them. They’re THE BEST Monster Cookies you’ll ever try. They happen to be gluten-free, too!

This Gluten-Free Monster Cookie recipe yields soft and chewy cookies that are full of peanut butter, oats, chocolate, and M&Ms. They are perfect for after-school snacks, play date treats, family gatherings, and pot lucks, or delivering to a friend. The fact that these Monster Cookies are Gluten Free is a bonus and one that no one will realize without you telling them!

I’ve been playing around with this recipe for a while now, giving my final batch to friends and family. They were an instant hit, and folks couldn’t believe they had no flour!

Processing half of the oats into oat flour adds the cohesive cookie texture everyone expects from a cookie. However, this is a step not to be skipped!

gluten free monster cookies

Ingredients and Estimated Cost

Per Serving Cost: $0.35

Recipe Cost: $8.41

  • 3 ½ cups old-fashioned oats – $1.74
  • 1 ¼ teaspoons baking soda – $0.01
  • 1 cup chunky peanut butter – $0.78
  • 8 Tablespoons unsalted butter – $0.88
  • 1 cup dark brown sugar – $0.44
  • ½ cup granulated sugar – $0.08
  • 2 large eggs – $0.46
  • 2 teaspoons vanilla extract – $1.32
  • ½ cup milk chocolate chips – $1.32
  • ½ cup peanut butter chips – $0.99
  • ½ cup plain M&Ms + more for garnish – $0.39

NOTE: The recipe prices are calculated by using grocery store websites. The actual cost of the recipe will vary depending on what ingredients you already have.

How To Make Gluten-Free Monster Cookies

  1. First, add two cups of oats to the food processor and process until the oats turn to flour. Then add the processed oats, the remaining oats, and baking soda to a medium mixing bowl and set aside. 
  2. Next, cream together the peanut butter, butter, and sugars in a stand mixer. Then mix in the eggs and vanilla before beating in the oats mixture. 
  3. Fold in the chocolate chips, peanut butter chips, and M&Ms. Cover the mixing bowl with plastic wrap and chill in the fridge for one hour. 
  4. Preheat the oven to 350 degrees F and line the cookie sheets with parchment paper. Use a 3-Tablespoon scoop to scoop cookie dough on the baking sheets. 
  5. Finally, bake for twelve to thirteen minutes, rotating the baking sheets halfway through until the cookie edges are lightly browned. Allow the cookies to cool on wire racks before serving. 

***For complete recipe instructions, see the recipe card below. 

gluten free cookies

Storage Tips

STORE: Cookies will keep covered in an airtight container for up to 4 days.

FREEZE: After scooping the dough into balls and placing them on the baking sheets, place the baking sheets in the freezer until the dough is firm. Then, transfer the dough balls to an airtight container and store them in the freezer for up to three months. 

Recipe FAQs

How many calories are in a gluten-free monster cookie?

One of these cookies has 401 calories in it. Please see the information at the bottom of the recipe card for the complete nutritional value information for these cookies.

What are monster cookies made of?

Monster cookies are made with simple ingredients that consist of oats, peanut butter, baking soda, butter, brown sugar, granulated sugar, eggs, vanilla, chocolate chips, peanut butter chips, and M&Ms. For a detailed list of the amounts of each ingredient, please see the recipe card below.

Can you freeze monster cookie dough?

Place scooped cookie dough on a baking sheet in the freezer until the dough is firm. Then, transfer the dough balls to an airtight container and store them in the freezer for up to three months. 

Monster cookies with oats, peanut butter, milk chocolate chips, peanut butter chips, and M&M's.

More Cookies

A close up picture of Gluten Free Monster Cookies stacked on top of each other.
4.71 from 17 votes

Gluten-Free Monster Cookies

Author Jillian
Recipe Cost $ $8.41
Serving Cost $ $0.35
Prep Time 1 hour 10 minutes
Cook Time 12 minutes
Total Time 1 hour 22 minutes
24 cookies
These Gluten-Free Monster Cookies are loaded with peanut butter, oats, and M&Ms. They have crispy edges and are soft and chewy.


  • food processor
  • stand mixer
  • Measuring cups
  • Measuring spoons
  • rubber scraper
  • baking sheets
  • parchment paper or silicone baking mats
  • wire rack
  • 3-Tablespoon cookie scoop




  • Add 2 cups of oats to the bowl of a food processor. Process until oats turn to flour.
  • Add processed oats, the remaining 1 ½ cups of oats, and baking soda to a medium bowl; set aside.
  • In a stand mixer bowl, cream together peanut butter, butter, and sugars on medium-high speed until light and fluffy, about 3 minutes.
  • Add eggs and vanilla and beat to combine. Add oats mixture and beat on low until fully incorporated.
  • Fold in chocolate, peanut butter, and M&M’s until evenly distributed.
  • Cover mixing bowl with plastic wrap and chill cookie dough in the refrigerator for 1 hour.


  • Fifteen minutes before baking, move the oven rack to the middle position and preheat to 350 degrees F.
  • Line cookie sheets with parchment or silicone baking mats.


  • Using a 3-Tablespoon scoop, scoop cookie dough and place it on a cookie sheet 3 inches apart.
  • Bake for 12-13 minutes, rotating cookie sheets halfway through baking until the edges of cookies are lightly browned.


  • Move cookie sheets to the wire rack and cool for 5 minutes. Remove cookies from cookie sheets, and cool on wire racks.


Serving: 1cookie | Calories: 404kcal | Carbohydrates: 56.4g | Protein: 10.5g | Fat: 16.7g | Saturated Fat: 6.6g | Cholesterol: 27mg | Sodium: 165mg | Potassium: 294mg | Fiber: 6.3g | Sugar: 20g | Calcium: 40mg | Iron: 2.5mg

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Recipe Rating


  1. They look amazing. I cannot belie they are gluten free

    1. That’s what everyone says when they taste one!

  2. Bintu - Recipes From A Pantry says:

    What a delicious looking cookie, and perfect for a lunch box treat. The oats make them guilt free too (well nearly)!

  3. Marsha | Marsha's Baking Addiction says:

    These cookies look absolutely delicious! I love peanut butter cookies!

  4. How cute are these! I bet kids would love helping to make them too and I love an Oat cookie.

    1. My kids love helping me make these cookies!

  5. Yum! These look SO GOOD and perfect for back-to-school. Love that they are loaded with oats and gluten-free! Pinning!

  6. Love your photos, these cookies look to die for!

  7. I wonder how these would work with Almond butter??

    1. Almond butter would work, too!

  8. If you don’t have a food processor, can you sub a different flour? 🙂

    1. I haven’t tried it with other flours, but if you’re not GF then you can use all-purpose. If you are GF then you can probably use GF all-purpose flour or even coconut flour.

  9. These cookies are awesome! They bring out the “cookie monster” in everyone who eats one! Thank you for a terrific recipe.

    1. Yay, I’m so glad you loved these cookies!

  10. I don’t process the oatmeal at all. My recipe is basically the same made by hand to keep from breaking down
    the oatmeal. I like the looks of yours better and can’t wait to try them. My seniors office aides at school love monster cookies!

  11. It was finally cool enough today to put the oven on and I was dying to make some cookies! Been such a long hot summer it feels like months since I was able to do any baking (and store bought cookies just are not as good as home made lol) I wanted a simple oatmeal cookie so I gave this a try. I’m not a GF person but I do have a family member who is. Thought I would try it and if I liked it I would pass on the link. I had to improvise with the add ins since my cupboard needs replenishing soon lol. I just used 1 cup of milk choc chips and 1 cup of salted caramel chips. I made them about 1 1/2 tablespoon in size and they took approx 10 minutes to bake. The first sheet didn’t flatten out at all so I pressed them down with my fingertips and that worked great. I got 42 cookies out of the batch – a lot more than I expected but I’m not complaining 🙂

    1. Glad these worked out for you, even with your improvising!

  12. Oh these cookies! Stop what your doing and make these ASAP! So so good. My celiac friend begs me to make these for her. My trick is to use the oat flour, plus I use 2 cups of quick oats instead of whole oats, better texture in my opinion. Yum

    1. Renee, I am thrilled that you and your friend love these cookies. I have a few friends that request these regularly! Thanks for stoppy by! 🙂

  13. If a person doesn’t have a food processor they might have coffee bean grinder takes a little more time but it still works

  14. Omg these are like crack. I made these to enjoy throughout the week and my husband and I have already each had three…whoops. I’m pregnant and have had such a sweet tooth lately and these definitely hit the spot. Just need to stop myself from eating them all!

    1. Alyssa,

      I know exactly what you mean. So glad you’re enjoying them! 🙂

      Good luck with your delivery.

  15. Awesome cookies! I make these all the time and my family loves them. No one even complains about them being gluten-free

    1. Kate, I am thrilled that this recipe has become a regular in your kitchen!

  16. This is one of the best cookie recipes I’ve ever made. I really love the addition of the oatmeal along with the other ingredients to give it even more chew and body.

  17. So perfect for back to school! Great treat to stick inside a lunch box! Definitely a family pleaser!

  18. I’m so glad I found this! I love finding gluten-free cookie recipes and these look so perfect! Thank you!

  19. I made these cookies over the weekend and my kids loved them! We will be making them often!

  20. These are amazing! My kiddos love them, thank you! I was wondering if after I bake them, could I freeze them?

    1. So glad you and your kids loved them! You can freeze them. Wrap them in two layers of plastic wrap, place them in a freezer-safe container or zipper-top bag, and freeze for 4-5 months. Then, thaw at room temperature for a few hours when you want to eat them again.