Soft-Baked Monster Cookies

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

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.

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. 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!

Monster oatmeal cookies

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 wait until your first bite!

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
  • 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 (160g) 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. Click here for my tips and tricks on freezing 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 information.
  7. Be sure to check out my top 5 cookie baking tips AND my 10 must-have cookie baking tools.

Keywords: cookies, oatmeal cookies, monster cookies

Monster Peanut Butter Cookies - the best monster cookies you'll ever make! @sallybakeblog


  1. Just made these-pretty good, but not the best Monster cookies I’ve ever made. I like recipes with more oatmeal and less or no flour. Also seem a little bland, maybe a little salt would help. Overall they are good, but not great.

  2. Excellent baking site! I’ve been a professional baker for 30 years and these are real recipes and done with professional techniques. The results are perfect.

  3. Ahhh! Such thick cookies! I could hardly believe my eyes when I saw this incredibly thick and soft cookies for the first time. Thick cookies are my favorite kind; the softer, the better, in most cases. But sadly, my brother has a very serious peanut allergy, so these peanut-butter and M&M-filled cookies aren’t possible for us :(. But, I would still love to have such an immensely thick cookie, so I thought I’d do a kind of super-thick chocolate hazelnut cookie. So, sub Nutella for the peanut butter and hazelnuts and more chocolate chips for the M&M’s. Would all that work? Thanks, Sally, I appreciate it!

    1. Nutella is a little thinner than the consistency of peanut butter, but you can try a 1:1 substitution. The cookies may not be as thick though!

    2. Wow! Wow! Wow! I don’t have words for these cookies. They are incredibly delicious. And SO thick! I have such a hard time getting my cookies to bake thick because of the high altitude that I live in (5000 ft). It boggled my mind that they came out so thick without even chilling. Thanks again for another incredible recipe Sally!

    3. These aren’t like traditional monster cookies. A little more peanut butter and less oats. But I like that. My only complaint is that this recipe and the chcoloate chip cookie one are both too crumbly. I did followthe suggestion of spooning flour into my measuring cups, but I am thinking I also need to cut back more too for optimum results.

    1. Such a great recipe, my daughter is allergic to all nuts. Substituted peanut butter with Biscoff cookie spread. And m&m with hersheyetts.

  4. Haven’t made these yet, wanted to ask, I had a monster cookie that was really good she said the recipe called for a tbsp of corn syrup.
    Having read just enough of your blog to think I knew something (ha..ha)
    I thought it was for more chew in the cookie. Wanted to know your thoughts. Thanks so much, your helping me to want to bake again.
    My favorite so far is you Oatmeal Raisin Cookies.

  5. Used unsalted butter which didn’t give enough flavor to the cookie – use salted butter as recipe says or add salt – after a day the cookies were very dry and crumbly – not sure why followed the recipe except for the salted butter.

  6. Quick, easy, and delicious! Made ahead and froze. Hand mixed and seemed to be ok. Used chunky peanut butter instead of creamy and liked the crunch. Could probably use other add ins like pecans etc. Was surprised how light colored they were. Had to refrain from baking longer. Will definitely make again!

    1. I’m so happy you enjoyed these monster cookies! This recipe is definitely a great base for add-ins of your choice! Would love to know what you try next time 🙂

  7. Used this rexipe as a guide for healthy cookies for kids :…used oil not butter, cut sugar down by 1/2 cup, used whole wheat flour, flax egg instead of an egg and no chocolate used. The house smelled insane when cooking these! Boy were they amazing!!!

    1. I made these cookies as recipe stated and they were so good!! good! sooo good!
      I do make them the “healthier” way too as stated in my original post, but the original recipe is the bomb!!! Like dream of when I can bake them again and come up with excuses to bake them again. This recipe comes out great in small batches too. I make a 1/4 batch only when I make them to reduce consumption 😉

  8. My granddaughter likes soft monster cookies so I googled for a monster cookie that included flour. Just took them out of the oven and love them. I’m ditching my all oatmeal recipe and this is now my standard. And loved that I didn’t have to chill the dough!

  9. These are DELICIOUS! The texture is wonderful and the flavor is perfectly balanced for your sweet tooth. Thank you for sharing!!!!!

    1. Mine came out crumbly as well when I made them this afternoon – almost dry? I followed the recipe exactly (butter & egg were at room temp, etc). I can’t think of why it didn’t work out as it was supposed to. I was worried they would be dry / crumbly as I was mixing them; the dough never seemed to be blended fully.

      I just did a taste test though, and honestly, who cares about looks or texture if they taste great? 😉

    2. Ues, I had the same trouble woth this recipe and her chcolate chip cookie one. Lots of good advice in the recipe and great tasting, but seems to need a little more moisture or cohesion.

  10. Looking for a monster cookie recipe with shredded coconut that is still soft. Could i add coconut to this without drying the cookies out?

  11. I love these cookies! Sally’s baking addiction is my go-to website for baking cookies. I have made this recipe a few times. The most recent time I used all natural off-brand peanut butter and it made the cookies pretty dry. It is worth spending a couple more dollars and getting the good stuff, will make a huge difference in the cookies.

  12. I’m a diehard Sally fan, and I come here first for EVERY baking recipe. But these cookies were a big fail for me and I can’t figure out why. They were dry and crumbly, you can’t even pick up a cookie whole, they just fall apart. I use a kitchen scale whenever possible, so I know I was precise with measurements.
    They also taste very bland, they’re not even sweet. I’ve gone over it 10 times trying to figure out what I did wrong and I can’t find any mistakes.

    1. Hi Colleen! I can’t help but wonder what kind/brand of peanut butter you used? I’m baffled why yours don’t taste sweet– there is plenty of sugar! Some peanut butters are thicker than others and could lead to a crumbly cookie. I use (and recommend) Jif creamy. Make sure you don’t chill the cookie dough either– from the mixing bowl to the oven right away. I hope this helps.

      1. Sally, I am so embarrassed, please delete my comment. I just realized that the stick of butter I used from a brand new package of Target brand butter is UNSALTED. The butter is in a newly redesigned RED box, and it turns out the red box is now Unsalted and the blue box is Salted – even though the old packages of Target butter were Red=Salted and Blue=Unsalted, so I didn’t even read it. That explains the blandness. Additionally, I used Skippy Natural creamy PB, and while I do not consider that a true “Natural PB”, it does contain less sugar and salt than normal PB which I did not even consider last night when I posted this. As for the dry, crumbly texture – after leaving them overnight, the cookies are now firm and stay together. Definitely drier than I expected, but I think that overall this recipe failure was a definite ME problem, and I really hope you will delete my original comment and accept my apology.

  13. I have been baking these cookies for at least two years now AND they are my FAVORITE cookie. In fact, I doubled the recipe recently so I could “share” but I may just eat them all! My entire family loves them. Thanks for the great recipe. It’s sure to be one that gets passed to my kids!

  14. These are absolutely delicious! And they look just like YOUR photo! Thanks for sharing such a great recipe Sally! My favourite cookie!

  15. I love your recipe! My son has a SEVERE peanut allergy so I just substitute with almond butter and Smarties. The expensive almond butter works as a great substitute for most recipes….not PeaButter (uses with peas rather than almonds). Also the peanut is related to peas and my son is beginning to develop an allergy to those as well. Thank you Sally…love your food 🙂

  16. Really good but if I made again I would add a 1/2 teaspoon of salt. Did use salted butter but still I felt the cookies needed a bit more.

  17. Loved these! Swapped chocolate chips for extra M&Ms. Kids loved help making them too. Onto another recipe of yours today! Thank you for providing these recipes for families who are stuck at home.

  18. It is safe to say that this is my favourite cookie recipe. It has everything a great cookie needs! I love the hearty texture the oats bring. The PB and chocolate combo is Absolute perfection. Easy to whip up in one bowl and freeze Some for later.

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I’m Sally, a cookbook author, photographer, and blogger. My goal is to give you the confidence and knowledge to cook and bake from scratch while providing quality recipes and plenty of pictures. Grab a cookie, take a seat, and have fun exploring! more about Sally