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Monster cookies are peanut butter cookies with oats, chocolate chips, and M&Ms. My easy monster cookie recipe yields extra soft and thick cookies and you don’t need to chill the cookie dough! 

Monster cookies with M&Ms

For as much as I love peanut butter cookies and oatmeal cookies, I’ve never published a monster cookies recipe on my blog before. To be honest, the reason I’ve never shared one is because it’s taken me almost 3 months to develop one I’m proud enough to publish. Too flat, too puffy, falling apart, rock hard, too dry, and too sweet peanut butter oatmeal cookies have all made their way in my kitchen lately. But I’ve finally found that “perfect” one and I’m so excited to show you!

Cookie dough balls on cookie sheet before baking

stack of 2 monster cookies

What Makes These Monster Cookies Different?!

My monster cookie recipe is unlike most traditional recipes. It’s more like a peanut butter cookie with oats, rather than an oatmeal cookie with peanut butter. Other aspects setting these monster cookies apart from the rest:

  1. Mega soft-baked texture
  2. Extra thick, just look at the picture!
  3. No dough chilling required

This recipe doesn’t make 5-6 dozen cookies like most monster cookie recipes requiring a hefty load of ingredients. Rather, my recipe uses a small amount of ingredients and yields 2.5 dozen medium-sized cookies. They aren’t actually “monster” in size, but feel free to roll them larger. Or try my one giant monster cookie recipe if you want a literal monster sized cookie!

Peanut butter oatmeal cookies

Quick Oats are Key

Use quick oats. Why? Quick oats are more finely cut whole oats and will give the monster cookies a more uniform texture. Furthermore, quick oats will act more as a binder since the consistency is more powdery. If you don’t have quick oats, pulse your whole oats in the food processor a few times to break them down.

Helpful tip: The cookies spread just slightly while baking, so press them down with a spoon after you remove them from the oven. That’s what gives the cookies their crinkled tops.

Quick Monster Cookies: No Dough Chilling!

Like I mentioned, this is a quick cookie recipe. Unlike your classic chocolate chip cookies or sugar cookies, there is no dough chilling needed for these monster cookies! The dough is thick and sturdy enough to bake right away. However, should you bake the monster cookies with a thinner peanut butter or on a particularly humid day, chill in the refrigerator for up to 30 minutes. Cookie dough can be picky. Go by how your dough feels. If it’s too sticky, chill for 30 minutes. If not, just bake.

More no dough chilling cookie recipes. I have tons! Snickerdoodles and shortbread cookies are two favorites.

Monster oatmeal cookies on a blue plate

These cookies remain exceptionally soft for days… if they last that long. I also find that the peanut butter flavor is intensified after day 1, too. Just like my favorite soft and thick peanut butter cookies. Now wait until your first bite!

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Monster cookies with M&Ms

Soft-Baked Monster Cookies

  • Author: Sally
  • Prep Time: 10 minutes
  • Cook Time: 20 minutes
  • Total Time: 40 minutes
  • Yield: 2.5 dozen 1x
  • Category: Dessert
  • Method: Baking
  • Cuisine: American


These are the best monster cookies ever! They’re deliciously packed with peanut butter, oats, M&Ms, and chocolate chips. No bite is boring! The cookies are soft-baked style and extra thick. No cookie dough chilling required, so this cookie recipe is simple and quick! 


  • 1/2 cup (1 stick or 115g) salted butter, softened to room temperature*
  • 1/2 cup (100g) packed light brown sugar
  • 1/4 cup (50g) granulated sugar
  • 3/4 cup (185g) creamy peanut butter
  • 1 large egg, at room temperature*
  • 1 teaspoon pure vanilla extract
  • 1/2 teaspoon baking soda
  • 1 and 1/4 cups (156g) all-purpose flour (spoon & leveled)
  • 1/2 cup (40g) quick oats*
  • 3/4 cup (150g) M&Ms (any size or variety)
  • 1/2 cup (90g) semi-sweet chocolate chips


  1. Preheat oven to 350°F (177°C). Line baking sheet with parchment paper or silicone baking mat.
  2. In a large bowl, using a hand-held mixer or stand mixer with paddle attachment, cream the butter and sugars together on medium speed, about 3 minutes. Mix in the peanut butter, egg, and vanilla (in that order). Scrape down the sides of the bowl as needed. Slowly mix in the baking soda and flour. Do not over-mix. On low speed, beat in the quick oats, M&Ms, and chocolate chips just until incorporated. If the dough is very soft and unmanageable by hand, chill the dough for 30 minutes before rolling.
  3. Rolls balls of dough, about 2 Tablespoons of dough per ball, onto prepared baking sheet. Press a few extra M&Ms on top for looks, if preferred. Bake for 11-13 minutes– the cookies will still look a little soft, which is recommended. Slightly press down the baked cookies with the back of a spoon, since the cookies only slightly spread in the oven. Allow cookies to cool on baking sheet for 10 minutes before transferring to a wire rack. Cookies will firm up as they cool.
  4. Store cookies covered at room temperature for up to 1 week.


  1. Freezing Instructions: Baked and cooled cookies freeze well for up to 3 months. Unbaked cookie dough balls freeze well for up to 3 months too. Bake frozen cookie dough balls for an extra minute, no need to thaw. Read my tips and tricks on how to freeze cookie dough.
  2. You can use unsalted butter in this recipe. If so, add 1/4 teaspoon salt with the flour.
  3. Peanut Butter: While it’s great for cooking and eating, natural style peanut butter isn’t ideal for these cookies. They will turn out too dry and crumbly. I do not recommend crunchy style peanut butter for that same reason. I recommend processed creamy peanut butter such as Jif or Skippy.
  4. Use quick oats in this recipe. Quick oats are more finely cut whole oats and will give the monster cookies a more uniform texture. Furthermore, quick oats act more as a binder since the consistency is more powdery. If you don’t have quick oats, pulse your whole oats in the food processor a few times to break them down.
  5. Looking for a recipe without peanut butter? Here are my Chewy Oatmeal M&M Cookies.
  6. Why is everything at room temperature? All refrigerated items should be at room temperature so the batter mixes together easily and evenly. Read here for more about the importance of room temperature ingredients
  7. Be sure to check out my top 5 cookie baking tips AND these are my 10 must-have cookie baking tools.

Keywords: cookies, oatmeal cookies, monster cookies

Reader Questions and Reviews

  1. I made these cookies for my dad for xmas two years ago. They were definitely a favorite! I usually make 3-4 different types of cookies for him and these were gone first. You won’t be disappointed!

  2. These are amazing. I also LOVE LOVE LOVE your Fudge Ripple Monster Bars from your ‘Baking Addiction’ recipe book . They are to die for!!!! I’m curious, have you ever tried freezing them? The bars that is. Do they freeze well? I’d love to do that but I’m afraid they won’t be as good.

    1. Hi Brittani! Thank you so much. Yes, they freeze wonderfully. Freeze squares between sheets of parchment paper for up to 3 months. Thaw in the refrigerator or at room temperature.

  3. I pinned this recipe ages ago and just now got around to making them. They are AMAZING!!! Seriously delicious, super rich, and soft cookies. We will definitely be making these again.

  4. I love love love this recipe. My cookies were perfect. Thank you for always posting the most precise recipes.

      1. Hi Gillian, natural style peanut butter isn’t ideal for these cookies. They will turn out too dry and crumbly.

    1. These cookies came out super dry and crumbly I followed the recipe exact even the creamy jiffy peanut butter ‍♀️

      1. Hi Kayla! How did you measure the flour? Make sure to spoon and level (instead of scooping) to avoid packing in too much flour into your measuring cups. You can read more about properly measuring baking ingredients in this post.

    2. This cookie is so delicious! I live in Florida and always have a problem with my cookies spreading and these did not! I didn’t have any M&Ms but I did have some Snickers bars left over from Halloween so I chopped those up and stirred them in. Fantastic!

  5. Another winner! These are amazing. Easy to throw together and a crowd pleaser. Thank you! I improvised and used while chocolate chips instead of m&ms because I had none of those.

  6. Love love love these cookies! I love how thick they are, they are kind of filling so I definitely can’t have too many in one sitting which is good. Super easy to make. Im sure I will be making a lot of these in my future

    1. We don’t recommend it, Jacinda. Best to stick with real butter, or try a vegan butter substitute such as Earth Balance brand (although we have not tested it in this recipe).

  7. This is the perfect recipe when you have a bunch of different kinds of chocolate chips/baking chips. I actually made these with whatever was in my candy bowl (I think it was a mix of reese’s pieces, pretzel m&ms and mini m&ms) and the bottom of some white chocolate chip and chocolate chunk bags. Perfect recipe to clean out the cabinets!

  8. Your. Recipe sounds the best out of all I have read today. My grandson wants a giant cookie like the size of a pizza today for his birthday an he wants Oatmeal raisen. Do you have any recommendations? Thanks

  9. Peanut allergy here. Can we make this with Almond butter? We use Barney Butter which has a similar consistency to peanut butter that’s more like JIF versus the natural stuff. Thanks!

    1. Hi Michi, we haven’t tested that particular almond butter, but let us know if you give it a try!

    2. I have a peanut allergy and used Barney almond butter (half smooth and half bare smooth). Cookies tasted great but were slightly delicate/crumbly. I also felt the recipe could have used a little salt so perhaps almond butter is not as salty as peanut butter?

  10. Perfect cookie and such a nice change from a chocolate chip or Oatmeal and the M&Ms give it a “I’m a happy cookie” look. Even though I’ve made thousands of cookies in my 70 years, I still read your Cookie Tips and paid particular attention to the butter. After 1 hour exactly, in my 75 degree home, my butter was exactly 65 degrees, per my Thermapen! I’ve had 100% success with every recipe I’ve made from your collection.

    1. Thank you so much for making and trusting our recipes, Shirley!

  11. This recipe looks great, so I am planning to make it this weekend. I have two questions though… 1. I want to do an assortment of add-ins like the M&M, choc chips, PB chips, heath bar bits, etc. I see the recipe has 1.25 cups total of M&M and choc chips. So, is 1.25 cups the max for add-ins, or can the cookie accommodate more without falling apart? 2. If I wanted to make a larger size cookie (4 tbl of dough), how long do I need to bake for? Thanks!

    1. Hi Jay, those additions sound delicious. We recommend sticking with 1.25 cups total add-ins. We’re unsure of the bake time for larger cookies, so keep a close eye on them in the oven. Hope they’re a hit!

  12. This recipe was exactly as described. Thick, fat, soft, chewy cookies. My favorite. So hard to go wrong with monster cookies. I added white chocolate chips and pretzels. Love that there’s no chill time. This will be my go-to monster cookie recipe.

  13. Good evening! I was wondering if I made these and used a 1/4 cup measure for the cookies, how long would they take to bake? Thank you

    1. Hi Sarah, we’re unsure of the exact bake time, but it will be longer. Keep a close eye on them and watch for browning on the edges of the cookies.

    1. Hi Mary, we suggest a 7×11 inch pan for monster cookie bars. A 9×13 inch pan would be stretching it. The bake time will be around 32-36 minutes at 350F, but use a toothpick to test for doneness.

  14. These are delicious and look beautiful. Made them for my grandkids and they loved them! This is a keeper for sure.

  15. I’ve made these several times and every single time I forget to pulse my Old Fashioned oats! They still taste great, though, and I’ve added Quick oats to my shopping list.

  16. Made these again, today, for company., at my twins’ request. They do not disappoint. So easy and so delicious! I could eat them without the M&Ms and chips.

  17. These are delicious and so easy! Highly recommend! My whole family loves them

  18. Yup… the reviews are true. These are fantastic! Baked for exactly 11 minutes with 2 tbsp dough balls and were baked to perfection!

  19. These cookies are begging for salt!! I didn’t notice there’s none in the recipe until I ate one. They also truly do not spread. With some salt, they’d be 5/5 for me—I will make the second batch with sea salt on top.

  20. These were tasty but they came out a little dry, could I have possibly over mixed them? Any suggestions? I definitely think it was an error on my part not the recipe but would love to perfect these

    1. Hi Amber, the first thing that could be causing these to be dry would be if you used too much flour–how did you measure your flour? We always recommend weighing it for the most accurate measurement, or spooning and leveling, as explained here. The other reason they could turn out dry is if you used natural peanut butter instead of the conventional processed kind, like Jif or Skippy. If those two things aren’t the culprit, then it could just come down to the climate where you live!

  21. I am baking for deployed soldiers who are stationed in very hot climates. We were instructed by our volunteer organization (Soldiers’ Angel Bakers) not to use butter because it can become rancid in very high heat. I made this recipe with butter flavored crisco instead. It came out dry and crumbly and the cookies were very thick. Ordinarily I would never use anything other than butter, but in this case, I had no choice. Any suggestions on how to modify recipes when using crisco?

    1. Hi Donna, We’ve never tested the recipe with crisco.. So you don’t waste your time and ingredients, you may want to find a cookie recipe that uses crisco.

  22. Yum. Im more of a chewy cookie person. But these are addictive!! Definitely making agian 🙂 thank you Sally.

  23. I weigh ingredients so other than bake time/discrepancy in oven temp, I can’t really say why my cookies tuned out dry. I baked them 11 minutes. Barely browned at the edges. One other possible factor is I got a new larger size kitchenaid and it doesn’t beat up smaller batches of dough amazingly… I will give these another try with a hand mixer…

  24. I love your recipes. This recipe is one I make often but I tweek it slightly. I use butterscotch chip and cut back the chocolate chips and m&ms. After years of making these, I’m just now reading the comments and finally understand why they tend to come out slightly dry and crumbly (still good though!) I’ve been using natural peanut butterThis batch is already destined for the dry side but next time, ill use regular peanut butter for the soft chewy variety. Thank you for sharing you amazing creations with us!

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