Tessa’s Recipe Rundown
TASTE: Loads of peanut butter, oats, chocolate chips, and M&Ms make these cookies so much FUN!
TEXTURE: Delightfully chewy thanks to the oats and peanut butter, with a subtle crunch from the chocolate chips and M&Ms throughout.
EASE: So easy! These cookies are ready to enjoy in just 33 minutes.
WHY YOU’LL LOVE THIS RECIPE: A family staple with no chilling required, but also freezer-friendly.
This post may contain affiliate links. Read our disclosure policy.
I’ve written an entire cookbook about cookie baking, and my cookie science experiments have been featured on NPR and People magazine and have even been used in university curriculums!
Needless to say, I love cookies. And my Monster Cookie recipe is something special. Thick, chewy, and loaded with my favorite ingredient… nostalgia 😉
It’s the perfect recipe for back-to-school season, Halloween, Christmas, or just any time I’m craving peanut butter and chocolate…which is basically every day, ha!
What Makes Cookies Chewy, Crisp, or Cakey?
My free guide reveals the ingredients and tweaks that matter.
Because it’s such an easy recipe, it’s a great one to make with kids. Oh, and it’s naturally gluten-free (if using certified GF ingredients)!
Sprinkle of Science
How to Make Amazing Monster Cookies
No Flour in This Monster Cookies Recipe?
Yes, these Monster Cookies are flourless cookies. The peanut butter, oats, and egg + egg yolk provide enough structure to hold everything together and bake into a chewy delight.
The lack of flour does change the texture of the dough. It will feel a bit loose and won’t hold together like a traditional cookie dough. This means that a few of the M&Ms and chocolate chips may fall out as you portion out the dough. That’s okay – simply add them back on top of each cookie dough ball! No biggie.
What Type of Peanut Butter is Best for Monster Cookies?
I recommend using natural peanut butter that’s been very well stirred (no oily pockets or dry bits).
My favorite is Kirkland Organic (high quality and a great price at Costco!). Natural peanut butter will yield a much bolder peanut butter flavor in these Monster Cookies. If you don’t have any, conventional peanut butter (Skippy / Jif) works well too.
What Type of Oats for Monster Cookies?
Use old-fashioned rolled oats for Monster Cookies. Don’t use quick oats, which can make the cookies mushier and less chewy. Be sure to measure correctly, as accidental over-measuring can cause dry, hard, crumbly cookies. Learn more about how to measure ingredients correctly here.
Do I Have to Use Dark Brown Sugar?
I recommend using dark brown sugar for its added flavor and moisture to achieve a rich and chewy cookie. You can use the same amount of light brown sugar instead, but note that your cookies may turn out lighter in color and slightly less moist.
Can I Use Almond Butter Instead?
We haven’t tested that in this Monster Cookie recipe, but a straight 1:1 swap of almond butter instead of peanut butter works perfectly in my Classic Peanut Butter Cookie recipe. Let me know if you give that a try here!
What Size Are These Monster Cookies?
I use a large 3-tablespoon cookie scoop to create perfectly chewy cookies. You can use a medium 1.5-tablespoon scoop instead and reduce the bake time by 1-2 minutes, but keep in mind that the smaller cookies won’t be as chewy.
Can I Mix up the Mix-Ins?
Yes! Feel free to use peanut butter chips, chopped Reese’s Pieces, or any other variety of mix-ins you like in these Monster Cookies – just keep them small in size and the total weight/volume the same amount for best results.
How to Prevent M&Ms From Cracking as They Bake
- Some bakers say that mini M&Ms are less likely to crack, and others claim that freezing your M&Ms prior to baking prevents cracking. I haven’t tested either theory, so I can’t say for sure how well they work.
- If the cracking bothers you, I recommend adding the additional M&Ms to the tops of each baked cookie as soon as they come out of the oven, before they have fully set.
- Be sure to press the M&Ms into each cookie thoroughly to ensure they adhere properly.
Can I Double This Recipe? Can I Halve This Recipe?
Yes! Double all ingredients to yield approximately 34 large cookies, or halve all ingredients to yield 8-9 large cookies. No other modifications needed.
Do I Have to Chill Monster Cookie Dough?
No, you can bake these Monster Cookies right after preparing the dough.
For extra chewy, ultra-flavorful cookies with a ton of PB flavor, I recommend chilling the cookie dough for 24 to 48 hours.
Avoid chilling any longer, as oats tend to zap moisture and these cookies will dry out. Learn more about how to chill cookie dough here.
How to Store Monster Cookies?
Monster Cookies can be stored in an airtight container at room temperature for up to 3 days. Store with a tortilla to keep the cookies softer for longer.
Can You Freeze Monster Cookies?
- Yes, Monster Cookies freeze well!
- If chilling the dough, do so before freezing.
- Place scoops of dough in a single layer on a parchment-lined rimmed baking sheet and place in the freezer until solid. Remove scoops to a labeled and dated airtight container.
- Bake directly from the freezer by reducing the oven temperature to 325°F and adding a minute or two to the bake time.
- Learn more about How to Freeze Cookie Dough (& Bake From Frozen) here.
More Cookie Recipes You’ll Love:
Monster Cookies
Email This Recipe
Enter your email, and we’ll send it to your inbox.
Ingredients
- 4 tablespoons (57 grams) unsalted butter, at cool room temperature
- 3/4 cup (203 grams) natural peanut butter, very well stirred*
- 1/2 cup (100 grams) granulated sugar
- 1/2 cup (100 grams) lightly packed dark brown sugar**
- 1 large egg plus 1 egg yolk, at cool room temperature
- 1½ teaspoons vanilla extract
- 2 cups (198 grams) old-fashioned rolled oats
- 1 teaspoon baking soda
- 1/4 teaspoon fine sea salt
- 1/2 cup (85 grams) semisweet chocolate chips, plus extra for garnish
- 1 cup (200 grams) M&M candies, plus extra for garnish
- Flaky sea salt, for topping, optional
Instructions
- Preheat the oven to 350°F. Line baking sheets with parchment paper.
- In the bowl of an electric mixer, beat the butter, peanut butter, granulated sugar, and brown sugar on medium-high speed until smooth and creamy, 2 to 3 minutes. Scrape down the bottom and sides of the bowl. Beat in the egg, egg yolk, and vanilla. Add the oats, baking soda, and salt, mixing on low speed until combined. Fold in the chocolate chips and M&Ms with a rubber spatula.
- Using a large spring-loaded scoop, measure out 3 tablespoon-sized balls of dough. Press the dough firmly into the scoop before placing it onto prepared baking sheets, spacing at least 2 inches apart. Dough will be loose. Dot the tops of cookies with a few M&Ms and/or chocolate chips before baking for picture-perfect cookies.
- If time permits: wrap the cookie dough balls very well in plastic wrap and allow to “marinate” in the fridge for 24-48 hours to enhance flavor and texture.
- Bake for about 13 minutes, or until the edges are slightly browned. Remove from oven and sprinkle flaky sea salt on top of the cookies, if desired. Cool for 5 minutes before removing to wire racks. For best texture and to allow the peanut butter flavor to fully develop, let cookies cool completely before serving.
- Cookies can be stored in an airtight container at room temperature for up to 3 days.
Recipe Notes
The Ultimate Cookie Handbook
Learn the sweet SCIENCE of cookie baking in a fun, visual way to customize your own recipes frustration-free. Plus, my best 50+ homemade cookies!
Photos by Joanie Simon.
I’ve been making these cookies from Tessa’s cookbook for several years and we love them because they are gluten free and delicious!
If you want to chill the cookie dough – do you need to pre-make the dough balls and wrap each individually with plastic wrap?
If you’d like to chill the dough, you can either chill the dough as a mass, or pre-scoop the dough balls and place them all in an airtight container for up to 48 hours. No need to individually wrap! Learn more about chilling cookie dough here 🙂
These were so much fun to make as well as tasty to eat! I refrigerated my dough overnight and instead of M&M’s, I used Unreal milk chocolate gems with food coloring for the eyes.
Sooo peanut buttery! Definitely follow the recommendation to use natural peanut butter! Wow! Yum! These remind me of no bakes (in a good way)!
These are my new favorite peanut butter cookies! They were so good!
I had never made cookies like this with no flour! I felt super nervous making them because they seemed like they weren’t coming together, but then they did after baking! Unfortunately, while most of the cookie tasted great, the m&ms came out tasting burnt (even though I was super careful not to over bake the cookies). Any tips on that?
How interesting! We didn’t experience that during our testing. Is it just the M&Ms on the tops of the cookies that tasted burnt? If so, next time, try adding them to the tops of each cookie immediately after baking them instead of prior to baking. That should fix the issue!
It was just the M&Ms. They split open during baking and had a charred sort of taste, which was so strange! I will try adding them after baking next time. Thanks!!
Did you by any chance bake them on the top rack of your oven? If so that could be why the M&Ms on top burned. Try baking them in the middle of the oven if that’s the case, and that should take care of it. Good luck!
Loved how easy and fast these were to make. Also enjoyed that these also happen to be gluten free. Who doesn’t love peanut butter and chocolate? And oats in cookies are under appreciated! Such a great combo in this recipe.
Super easy to make! My gluten free friends were appreciative and my non gluten free friends loved them! Doubled the recipe and made them smaller to feed a crowd.
I forgot to add the star rating!
These cookies were yummy, and so easy to make! I was concerned about the texture of the dough at first…the balls looked more like granola bites. But they’re turned out great!
The best monster cookies! They were gone fast! Make a double batch 🤣
Love these cookies and they are so much fun to decorate! Couldn’t be easier and the flavor and texture are amazing!