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
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.

FREQUENTLY ASKED QUESTIONS
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.
Try adding raisins, toffee bits, candy, candy coated sunflower seeds, chopped nuts, Reese’s Pieces, mini caramel cups, or mini peanut butter cups.
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.
Use an ice cream scoop to help make all of the cookies the same size and don’t crowd your cookie sheet.
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.
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.
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.
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.
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.
Once you have your cookies scooped out into balls, place a few M&Ms and chocolate chips decoratively on top before baking.
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.


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HOW TO STORE MONSTER COOKIES
- 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.



Ingredients
- 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
Instructions
- 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.
Nutrition
Photos used in a previous version of this post.
There is no flour amount listed in the ingredients but yet directions say to mix until you see no flour. Help!
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.
Really good cookies. Not a strong flavor or peanut butter which we like. Great texture.
My kids will devour a whole batch of these in minutes! Look SO good!
Thanks, Sandra!
Time to make a double batch of these start kick off spring break.
My kids love these cookies!
These cookies look so good! I want them for breakfast!!
I won’t judge!
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!
That’s awesome!
So so so great i make these all the time and its a neighbourhood favourite!
So happy to hear!
My kids love these! They usually pick out all of the m&ms first and then eat the cookie. They’re so good!
They sound like smart kids!