Oatmeal Peanut Butter Monster Cookies {Gluten Free}

Oatmeal Peanut Butter Monster Cookies – loaded with chocolate chips, M&M’s, peanut butter, and oats, these cookies are absolutely incredible from first to last bite!

These addicting cookies were gluten free before it was popular, and no one misses the flour. 🙂

What is a monster cookie?

If you’ve never had one before, you are in for a treat! Monster cookies are oatmeal peanut butter cookies that are also loaded with chocolate chips and M&M’s. Usually they call for simply oats, no flour, so they are a great option for those with gluten intolerance. 

REASONS YOU NEED TO MAKE PEANUT BUTTER MONSTER COOKIES:

• CHOCOLATE + PEANUT BUTTER = One of the best flavor combinations in the world!
• All those M&M’s not only make the cookies taste good, they make them so fun and colorful.
• They are packed with peanut butter flavor.
• Oats add perfect texture and makes them hearty with great crunchy texture.
• A bit of corn syrup (or honey) keeps them soft and chewy.
• All of your gluten free friends can eat them, but no one else will guess that they are gluten free.
• They freeze perfectly!

I got this monster cookie recipe over a decade ago and to this day they are my husbands very favorite cookie. With over fifty cookie recipes posted, that’s saying something!

Every time I share these easy monster cookies with family or friends I get rave reviews. They are soft, chewy, and yummy.

BEST MONSTER COOKIE RECIPE FOR SHARING

This recipe makes a huge, ginormous batch! We love stacking a few of them on paper plates and taking them to neighbors. They are also fun for Christmas cookie trays made with red and green M&M’s.

If I’m not sharing them or making them for a large group, I freeze them. I wrap a few together in plastic wrap and then store them in a large ziplock bag in the freezer. They last for 4-5 months.

They are fantastic heated up in the microwave for a few seconds. Or even eaten straight from the freezer. 😉

To see the complete printable recipe card, simply scroll to the bottom of the post.

How do you make monster cookies?

INGREDIENTS NEEDED:

• butter – I use salted butter in all of my baking recipes.
• creamy peanut butter – Using crunchy peanut butter will result in dry cookies, because some ofthe creaminess is replaced with chopped nuts. And as always, natural peanut butter doesn’t work well for baking. It’s best to stick with Jif or Skippy.
• granulated sugar and brown sugar – Both add sweetness, and the brown sugar adds a deep rich flavor.
• corn syrup – Just a bit makes the cookies extra chewy. You can substitute honey if you prefer.
• vanilla extract – Feel free to use your favorite brand.
• baking soda – Gives the cookies a bit of  rise.
• salt – Salt enhances the flavor of the cookies.
• large eggs – Since there is no flour in the cookies, eggs bind them together. Make sure your eggs are large.
• M&M chocolate candies -We usually use the plain milk chocolate M&M’s, but you can use any variety you like. The mini baking M&M’s also work well.
• chocolate chips – We like these best with half milk chocolate and half semi sweet chocolate chips.
• old fashioned oats – Quick oats will work, but they make for cookies that are a bit more dry. They won’t spread as much on the pan, they will be thicker. Make sure to use certified gluten free oats if you will be serving them to anyone with gluten intolerance.

DIRECTIONS:

1. PREP WORK: Soften your butter to room temperature. It’s best to let it sit out on the counter for a few hours. Preheat your oven to 350 degrees. Line your cookie sheets with silicone liners or spray with non stick cooking spray.
2. WET INGREDIENTS: Cream butter, peanut butter, sugars, corn syrup, vanilla, soda, and salt in a large mixing bowl till very creamy, about 2-3 minutes. Add the eggs and mix well.
3. DRY INGREDIENTS: Stir in the M&M’s, chocolate chips, and oats till well combined. (Dough will be fairly sticky.)
4. FORMING: Drop dough by tablespoonfuls onto prepared cookie sheets. For more round cookies, roll them into balls after scooping. These cookies don’t spread as much as most, so make sure you flatten the dough balls slightly with your palm or the bottom of a glass.
5. BAKING: Bake at 350° for 9-10 minutes. Don’t over bake or they will be dry and crumbly.
6. COOLING: Let cookies sit on the cookie sheet for about 5 minutes before removing to wire racks to cool completely. If you try to move them too soon, they will fall apart.

HOW TO STORE MONSTER COOKIES:

Because this recipe makes such a large batch, you will probably have leftovers. Thankfully, they freeze really well. After they are cool, I place them in heavy duty ziplock bags. They will keep in the freezer for 4-5 months. 

You can also just store them at room temperature. They are perfect for 3-4 days. They will last for up to a week, but they will dry out a bit.

FLOURLESS MONSTER COOKIES VARIATIONS: 

• Instead of chocolate chips, try butterscotch chips, peanut butter chips, or Reese’s pieces.
• To make giant monster cookies, portion the dough into 36 cookies instead of 72. When I do this, I like to flatten the cookie dough balls down a little with my palm before baking. They will need to bake about 14 minutes.
• For extra crunch, you can add some chopped peanuts to the dough.
• Add a pinch of cinnamon to the batter with the dry ingredients. (or more if you really like cinnamon)

Why are my Monster Cookies falling apart?

• If you use crunchy peanut butter, there isn’t enough smooth peanut butter holding the cookies together. 
• Not using large eggs can also make the dough too dry, making for crumbly cookies that fall apart.
• If you add too many mix-ins, it throws of the amount of binding ingredients in the dough, and they can’t hold together. 
• Moving them from the cookie sheet while they are still piping hot can also cause them to fall apart. Let them cool for 5 minutes before moving to cooling racks.

Other family favorite cookie recipes:

• Old Fashioned Peanut Butter Cookies
• Mint Truffle Kiss Cookies
• Brookies
• Peanut Butter Blossoms
• Roll and Press Sugar Cookies
• Pudding Chocolate Chip Cookies
• Cream Cheese Chocolate Chip Cookies
• Chewy Chocolate Cookies
• Easy Shortbread Cookies
• Best Snickerdoodle Recipe
• Orange Creamsicle Cookies

Oatmeal Peanut Butter Monster Cookies

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Yield: 6 dozen

Oatmeal Peanut Butter Monster Cookies

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My family's favorite oatmeal cookie. Loaded with peanut butter, chocolate chips, and M&M's. Always a hit!

Prep Time 19 minutes

Cook Time 10 minutes

Total Time 29 minutes

Ingredients

• 1 cup butter, softened to room temperature
• 3 1/4 cups creamy peanut butter
• 2 1/3 cups brown sugar
• 1 1/2 cups sugar
• 1 1/2 tsp corn syrup or honey
• 1 1/2 tsp vanilla
• 4 tsp baking soda
• 2 tsp salt
• 6 eggs
• 2 1/2 cups M&M's
• 1 cup milk chocolate chips
• 1 1/2 cup semi sweet chocolate chips
• 9 cups old fashioned oats

Instructions

1. Soften butter to room temperature. Preheat oven to 350 degrees.
2. Cream butter, peanut butter, sugars, corn syrup, vanilla, soda, and salt in a large mixing bowl till very creamy, 2-3 minutes. Add the eggs and mix well.
3. Stir in M&M's, chocolate chips, and oats till well combined. (Dough will be fairly sticky.)
4. Drop dough by tablespoonfuls onto silicone lined or greased cookie sheets. Flatten slightly with your palm.
5. Bake at 350° for 9-10 minutes.

Notes

-There is no mistake, these cookies have no flour.

-These cookies don't spread as much as traditional cookies, so you can flatten the dough a bit before baking.

-I find that using old fashioned oats is best, the quick oats make a drier cookie.

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• 
  OXO Good Grips Medium Cookie Scoop
• 
  Peanut Butter Measuring Cup

Nutrition Information:

Yield:

72

Serving Size:

1
Amount Per Serving: Calories: 206Total Fat: 11gSaturated Fat: 4gTrans Fat: 0gUnsaturated Fat: 6gCholesterol: 23mgSodium: 221mgCarbohydrates: 24gFiber: 2gSugar: 14gProtein: 5g

Did you make this recipe?

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(originally published 4/28/2009, updated May 2021)

Trust me, these chewy monster cookies are going to be a big hit wherever you serve them! They make a very large batch, but you can cut them in half if you so desire. But they are so tasty we like to keep extras in the freezer.