Monster Cookies

from 422 votes

Preheat your oven for a classic flourless Monster Cookies recipe that’s been in my family for more than two decades.

Monster Cookies studded with mini chocolate chips and M&Ms

Chocolatey, chewy, peanut buttery goodness. There’s no better way to describe this tried and tested family recipe for Monster Cookies.

My mom got this recipe from a friend more than 25 years ago, and it’d be impossible to count just how many dozens of Monster Cookies have been baked and enjoyed since that glorious recipe exchange.

Stand mixer bowl with monster cookies batter, mini chocolate chips and M&Ms

These cookies became a staple of mine when I was in college and grad school, and to this day, I’m remembered for their impossibly chewy and soft texture, and of course their unbeatable taste.

Unbaked cookies on baking sheet with cookie scoop

My husband jokes that these are a healthy dessert, courtesy of the lack of flour and addition of oats and peanut butter. While “health food” may be a stretch, you can guarantee they are a crowd-friendly dessert. (But if you are looking for a healthy sweet, don’t miss my famous 5-Minute Frozen Yogurt!)

Freshly baked monster cookies cooling on wire rack

The creepy candy eyes are an optional addition, but they’re a festive decorative touch in October when all things Halloween rule the food scene.

No stand mixer? No problem! I made these cookies dozens of times all through college sans mixer. (Consider the stirring your workout for the day.) And both smooth and chunky peanut butter will work, but I love the added crunch that chunky offers.

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Monster Cookies

Chocolatey, chewy, peanut buttery goodness. There's no better way to describe this tried and tested family recipe for Monster Cookies.
Author: Kelly Senyei
4.92 from 422 votes
Monster Cookies studded with mini chocolate chips and M&Ms
Prep Time 15 minutes
Cook Time 20 minutes
Total Time 35 minutes
Servings 24 cookies


  • 1 cup sugar
  • 1 cup packed light brown sugar
  • 1/2 cup unsalted butter, at room temperature
  • 3 large eggs
  • 1 1/2 cups peanut butter (smooth or chunky)
  • 1 Tablespoon vanilla extract
  • 2 teaspoons baking soda
  • 1/2 teaspoon salt
  • 4 1/2 cups oats (Old Fashioned or Quick)
  • 1 cup mini M&Ms
  • 1 cup mini-chocolate chips
  • Candy eyes (optional)


  • Pre-heat the oven to 350°F. Line two baking sheet with parchment paper or Silpat baking mats. 
  • In the bowl of a stand mixer fitted with the paddle attachment, cream together the sugar, brown sugar and butter until light and fluffy. 
  • Beat in the eggs, one at a time, and then beat in the peanut butter, vanilla, baking soda and salt until well combined.
  • Add the the oats and mix until combined, then add the mini M&Ms and mini-chocolate chips.
  • Scoop 2-to 3-tablespoon mounds of the dough onto the prepared baking sheets, spacing the mounds at least 2 inches apart. 
  • Bake the cookies for 12-15 minutes then remove them from the oven and allow them to cool for 5 minutes on the baking sheets before transferring them to a rack to cool completely. (See Kelly's Note.)

Kelly's Notes

The best way to guarantee your cookies are chewy and not too crispy is to underbake them slightly then remove them from the oven and allow them to cool for 5 to 10 minutes on the baking sheets.
If you're using the candy eyes, add them to the cookies immediately after you remove them from the oven.
★ Did you make this recipe? Don't forget to give it a star rating below!


Calories: 343kcal, Carbohydrates: 41g, Protein: 7g, Fat: 17g, Saturated Fat: 6g, Cholesterol: 33mg, Sodium: 269mg, Potassium: 179mg, Fiber: 2g, Sugar: 29g, Vitamin A: 185IU, Vitamin C: 0.1mg, Calcium: 45mg, Iron: 1.3mg


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Recipe by Kelly Senyei of Just a Taste. Please do not reprint this recipe without my permission. If you'd like to feature this recipe on your site, please rewrite the method of preparation and link to this post as the original source.

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  1. 5 stars
    I must update my review! I made these last Sunday and they were so good I made them again this Sunday! I hate it when people talk about all the changes they make to recipes to the point it is not even close to the same thing! I do however have to share a change I made though, because it added SO MUCH texture to the cookies! I didn’t have enough oatmeal and I didn’t want to run to the store in the middle of preparing these, so I added a cup of crushed up Corn Flakes! I don’t know if crushing them was necessary, but I thought it would be best to make it the size of the oatmeal. Let me tell you!!! I will do this again and again! It was so good! I used a half cup measuring scoop filled about 3/4 full and flattened them a little bit. It made about 16 cookies.

  2. 5 stars
    Perfect! I made 3″ cookies and ended up with a few extras. I took them out and flattened them before baking for the final 2 minutes.

  3. 5 stars
    This is by far the best monster cookie recipe I have ever used. They are so soft and delicious, they go too quickly so I have to make multiple batches every time!

  4. 5 stars
    This recipe turned out great!! I was worried they’d crumble with no flour but they look exactly like the pictures!

  5. I searched for this recipe. A former coworker had given it to me and, over the years, I’ve managed to lose it. It needed to be THIS recipe because my daughter and I are sensitive to gluten, and this recipe can easily be gluten free since it doesn’t have flour. Heading to the kitchen now to make a batch. YUM!

  6. 5 stars
    Very good!! My oven is getting pretty old so it was a fine line for me to get them done in the middle but not overdone so they were still soft and chewy. I must have did ok though because my test group (the guys at work) told me to make sure to keep this recipe! Love that this recipe has more peanut butter; yum!

    1. 5 stars
      These were so delicious! I tried blending 2 cups of the oats in the food processor and pushing the dough balls down and the results were 100/10. They are incredibly good.

  7. 5 stars
    I made I few minor changes to your awesome recipes, I wanted to share. I swapped one cup of oats for one cup shredded coconut, and bag of Reese’s peanut butter baking cups and candy 8.5oz bag for the candy and mini chocolate chips. And when I make them for my daughter who is allergic to chocolate I use Reeses pieces and peanut butter chips

  8. 5 stars
    I made these for a Friendsgiving in 2023. They were a total hit and when my buddy asked if he could take the leftovers to another event that weekend, I was fine with it. They were completely gone before the night was over with the hostess complimenting my buddy on the cookies. This recipe will be in my holiday cookie rotation moving forward.

    Thank you for sharing this recipe!

  9. Hello, mine turned out super flat after 15 minutes. I put the mixture in the fridge for 20-30 minutes prior and it was moist, almost falling apart when I spooned them on the tray. Where did I go wrong? Maybe over beat the sugar and butter at the beginning? Still tasted great, just wanting to perfect the presentation.

      1. 5 stars
        These are fantastic cookies – super moist, tasty and turned out just like the pics!

        Can you sub in something else to replace the peanut butter if there is a nut allergy?

      2. I’m so thrilled you enjoyed the recipe, Asha! I’ve never tried a different type of butter (like sunflower seed), so I’m not sure!

  10. 4 stars
    I either did something wrong or I’m not a huge fan of all oats/no flour cookies. The middle seems not done? Is that how it’s meant to be? The only thing I can think I might have made a mistake with is creaming the butter and sugars. My butter sat out for an hour prior to using but it still was somewhat cold. I wasn’t able to get a “light and fluffy” texture creaming it with the sugars as the recipe describes. Is this where I went wrong!? Either way the flavor is still amazing!! Just wish the middle of the cookies didn’t seem so “raw”.

    1. Hi Kristi! Did you confirm your oven temp was correct and your rack was in the center? It sounds like a temperature issue!

  11. 5 stars
    I love these cookies! I have made them many times. I had a craving for them today but not enough m&ms so I added what m&ms I had and threw in some Reese’s pieces for good measure. Yummy! Thanks for sharing this recipe.

  12. Hi! I was wondering if there was a way to half this recipe? I know it calls for three eggs, and I’m not sure if it’s possible to only make a half batch. Thanks!

    1. Hi Emerson! Halving the egg gets tricky, however this dough freezes beautifully and will last for months if stored in an airtight container.

  13. Hello Kelly,
    I’ve made monster cookies for years and years. The recipe I normally use is from an old church cookbook. The main difference is the old recipe calls for a spoon of Karo syrup. I’m not sure why it calls for it.
    I’m going to use your recipe this time. I’m sure my grandchildren will love them.
    Thank you for sharing your recipe, MaryAnn

  14. Taste great. Soft and chewy with just a bit of crunch. I reduced the sugar, seems like you can do that in many recipes and they’re still great. And, for a little salty crunch, I threw in some crushed up pretzels. Complements the peanut butter and chocolate well.

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