Monster Cookies

24 cookies
Prep Time 10 minutes
Cook Time 15 minutes
Total Time 25 minutes

Monster Cookies are peanut butter oatmeal cookies with chocolate chips and M&Ms mixed in that are naturally gluten free!

Peanut butter cookies are the most popular Cookies on the blog including Peanut Butter Blossoms, Peanut Butter Cup Cookies and Peanut Butter Cookies.

Monster Cookies on baking sheet


Monster Cookies are like kitchen sink cookies because they’re basically full of all the delicious flavors you could imagine wanting in a cookie, and yet they taste totally well balanced and delicious.

Even though they’re naturally gluten-free without using any all-purpose flour, they are still chewy from the use of both rolled oats and instant oats. If you want the cookies to be a bit less chunky, a favorite trick for these cookies is to pulse the instant oats in a food processor until they’re half powdered. (While the ingredients for these cookies are gluten-free, oats are often processed in plants that also process wheat, rye, and/or barley, which all have gluten, so make sure your oats are not contaminated if you’re trying to make a gluten-free cookie!)

In this recipe (and pictured here) the instant oats are not processed, but if you want them to taste less firm you can add more instant oats and put them in a food processor until it makes them into a flour.

Monster Cookies Collage


What is the best peanut butter for Monster Cookies?

This recipe uses smooth peanut butter but many people who want to add more texture will use chunky peanut butter. Natural peanut butter is not recommend for this recipe as the texture isn’t firm enough to hold together the recipe.

What else can be mixed into Monster Cookies?

Try adding raisins, toffee bits, candy, candy coated sunflower seeds, chopped nuts, Reese’s Pieces, mini caramel cups, or mini peanut butter cups.

Do you really need to use both kinds of oats?

This recipe calls for both rolled oats and instant oats (or quick oats – they’re the same thing). Do not skip using both varieties of oats. The rolled oats will give the cookies chew and texture while the instant oats will keep the cookies tasting softer and more like they have some flour in the recipe.

How do I make the cookies uniform and even?

Use an ice cream scoop to help make all of the cookies the same size and don’t crowd your cookie sheet.

What other candies can be used in this recipe?

You can use other candy instead of M&Ms with this recipe. Try peanut butter chips, mini marshmallows, white chocolate chips or dark chocolate chips, butterscotch, or caramels. Or check out these Oatmeal Reese’s Peanut Butter Cookies.

What if I don’t have a stand mixer?

If you don’t have a stand mixer, you can cream the butter and sugar together with an electric hand mixer, or just do it with a bowl and a spatula.

Can these cookies be made crunchy?

You can make these cookies less chewy and more crunchy by adding a few minutes to the cooking time, but remember that because they are flourless, they already won’t be as chewy as most cookies normally would be.

How do you keep cookies from sticking to the baking sheet?

Make sure to line your cookie sheet with parchment paper, unless your sheet is non-stick, but even then it’s a good idea to line them just in case. If you have a silicone baking mat, that is even better than using a parchment paper liner.

Why are my cookies uncooked in the middle?

If your cookies turn out under-baked but browned on the outside, your oven may not be cooking true to temperature. Try using an oven thermometer to make sure it’s heating right. Since your cookies will have such a firm texture it may be hard to know if the inside is under-baked.

How do I make these cookies look picture perfect?

Once you have your cookies scooped out into balls, place a few M&Ms and chocolate chips decoratively on top before baking.

Can I use this recipe for large bakery style cookies?

If you want to make a giant monster cookie use a ½ cup measure to measure out the cookie, roll to 1 inch thickness, lower the temperature to 325 degrees and cook for 18-20 minutes and watch for the edges to brown.

Monster Cookies stacked on table with glass of milk



  • Serve: Monster cookies can be kept in an airtight container at room temperature for 4-5 days.
  • Store: It is not recommended to refrigerate most cookies because they can harden compared to room temperature cookies.
  • Freeze: Freezing cookie dough is much better than the baked cookies. Scoop the dough with your cookie scoop onto a baking sheet and freeze the scoops. Defrost in your refrigerator until fully defrosted then follow the cooking instructions for your monster cookie recipe. Monster cookie dough will last for about a year in the freezer.
Monster Cookies on table with glass of milk

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Monster Cookies

Monster Cookies are peanut butter oatmeal cookies with chocolate chips and m&ms mixed in that are naturally gluten free!
Yield 24 cookies
Prep Time 10 minutes
Cook Time 15 minutes
Total Time 25 minutes
Course Dessert
Cuisine American
Author Sabrina Snyder


  • 1/2 cup unsalted butter , softened
  • 1 cup brown sugar , packed
  • 1/2 cup sugar
  • 3 large eggs
  • 1 1/2 cups peanut butter
  • 2 teaspoons vanilla extract
  • 2 teaspoons baking soda
  • 3 cups rolled oats
  • 2 cups quick oats
  • 1 cup semi-sweet chocolate chips
  • 1 cup M&M candies


  • Preheat oven to 350 degrees.
  • To your stand mixer add the butter, brown sugar and sugar and beat until light and creamy, about 2-3 minutes.
  • Add in the eggs one at a time then add in the peanut butter until smooth.
  • Add in the vanilla, baking soda, rolled oats, chocolate chips and M&Ms and combine.
  • Scoop with an ice cream scoop 3 inches apart and cook for 13-15 minutes.


Calories: 338kcal | Carbohydrates: 37g | Protein: 7g | Fat: 18g | Saturated Fat: 7g | Cholesterol: 32mg | Sodium: 183mg | Potassium: 227mg | Fiber: 3g | Sugar: 22g | Vitamin A: 170IU | Vitamin C: 0.1mg | Calcium: 42mg | Iron: 1.8mg

Monster Cookies Collage

Photos used in a previous version of this post.

Monster Cookies on baking sheetMonster Cookies with Peanut Butter, Oats, Chocolate Chips, and M&MsMonster Cookies with M&Ms and chocolate chipsgluten free monster cookies

About the Author: Sabrina Snyder

Sabrina is a professionally trained Private Chef of over 10 years with ServSafe Manager certification in food safety. She creates all the recipes here on Dinner, then Dessert, fueled in no small part by her love for bacon.

Sabrina Snyder is a professionally trained personal and private chef of over 10 years who is the creator and developer of all the recipes on Dinner, then Dessert.

She is also the author of the cookbook Dinner, then Dessert – Satisfying Meals Using Only 3, 5 or 7 Ingredients, published by Harper Collins.

She started Dinner, then Dessert as a business in her office as a lunch service for her coworkers who admired her lunches before going to culinary school and becoming a full time personal chef and private chef.

As a personal chef Sabrina would cook for families one day a week and cook their entire week of dinners. All grocery shopping, cooking and cleaning was done along with instructions on reheating. As a private chef she cooked for private parties and cooked in family homes in the evenings for families on a nightly basis after working as a personal chef during the day.

Sabrina has been certified as a ServSafe Manager since 2007 and was a longstanding member of the USPCA Personal Chef Association including being on the board of the Washington DC Chapter of Chefs in the US Personal Chef Association when they won Chapter of the year.

As a member of the community of food website creators Sabrina Snyder has spoken at many conferences regarding her experiences as a food writer including the Indulge Food Conference, Everything Food Conference, Haven Food Conference and IACP Annual Food Professionals Conference.

Sabrina lives with her family in sunny California.

Dinner, then Dessert, Inc. owns the copyright on all images and text and does not allow for its original recipes and pictures to be reproduced anywhere other than at this site unless authorization is given. If you enjoyed the recipe and would like to publish it on your own site, please re-write it in your own words, and link back to my site and recipe page. Read my disclosure and copyright policy. This post may contain affiliate links.


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  1. There is no flour amount listed in the ingredients but yet directions say to mix until you see no flour. Help!

    1. I’m so sorry. There isn’t any flour in this recipe as it’s naturally gluten-free. I’m not sure how that wording got in there. I’ve edited it to remove the flour portion. I hope you enjoy them.

  2. My kids are like Jen’s kids (comment above) lol. They pick out all of the M&M’s, then eat the cookie! Great recipe!

  3. My kids love these! They usually pick out all of the m&ms first and then eat the cookie. They’re so good!