Soft-Baked Monster Cookies.

Super soft and thick peanut butter cookies with oats, chocolate chips, and M&Ms. 

Quick and easy Soft-Baked Monster Cookies |

“Monster Cookies” are peanut butter oatmeal chocolate chip M&M cookies. For as much as I love peanut butter and oatmeal cookies, it’s quite surprising to see no basic peanut butter oatmeal cookie recipe in my archive.  To be honest, the reason I’ve never shared one with you 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 and out of my kitchen lately.  But not this one.  Oh my heavens.  I’ve finally found that “perfect” one.  I am so excited to show you!

As I mentioned above, “monster cookies” are peanut butter oatmeal cookies stuffed to the brim with colorful M&Ms and chocolate chips.  Today’s recipe is unlike most traditional monster cookie recipes though.  It’s more like a peanut butter cookie with oats, rather than an oatmeal cookie with peanut butter.  Still with me?

Also putting these monster cookies apart from the rest is that they are “soft-baked.”  My favorite cookie term.  Soft, tender, chewy, and moist in every bite.  Quite unlike the crunchy hard peanut butter cookies you are used to. And finally, my version is stuffed with a variety of M&Ms.  Peanut Butter M&Ms, classic M&Ms, and mini M&Ms all paid a visit to my monster cookie dough.

Soft-Baked Monster M+M Cookies |

Also good to know ahead of time is that my recipe doesn’t make 5-6 dozen cookies like most monster cookie recipes I’ve seen out there that use 3 eggs, 4 cups of flour, 4 cups of oats, 1 pound of butter, etc.  Rather, my recipe uses a fair amount of ingredients and yields just 2.5 dozen medium-sized cookies, so they aren’t actually “monster” in size, but feel free to make them larger.  Oh and bonus: it can all be mixed up in ONE bowl.

It’s an easy peasy, manageable, and quick recipe. Let’s begin!

You’ll start with the same step a lot of my cookie recipes begin with: cream your butter and sugars together.  Like usual, I’m using more brown sugar than white sugar in this cookie recipe.  Brown sugar gives the cookies a much softer, chewier, & moist consistency while the white sugar induces spreading.  It’s important to use both in today’s recipe.

What I particularly love is that the total amount of sugar is only 3/4 cup in the entire batch.  Quite low compared to most other peanut butter oatmeal cookie recipes you’ll find. Next, mix in the peanut butter, egg, and vanilla.  The recipe uses a ton of peanut butter.  Like I said, it’s more of a peanut butter cookie with oats rather than an oatmeal cookie with peanut butter.  Each bite packs intense peanut butter flavor.  In my world, the more peanut butter, the merrier. ;)

Quick and easy Soft-Baked Monster Cookies |

Next on the list is to add your dry ingredients.  Add the flour and baking soda to the same bowl in which you creamed the wet ingredients.  No extra dishes to dirty, here.  One bowl and you’re done.  I love recipes like this!

 Finally, mix in the oats. Please use quick oats here. Why? You need the slightly finer size from the quick oats in order to give the cookies a more uniform texture.  Quick oats will act more as a binder in this recipe than whole oats would, since the consistency is more powdery and the oats are smaller in size.  I actually did not have quick oats at the time, so I ground up my oats in a food processor for a quick 10 seconds to break them down.

I prefer whole rolled old-fashioned oats in my granola and granola bar recipes, but find using quick oats in this cookie recipes works best.

Last up is your add-ins, 3/4 cup of M&Ms and 1/2 cup of chocolate chips.  I keep a candy jar of M&Ms on my counter and it currently has a variety of all different kinds.  I used a mixture of peanut butter, mini, and regular M&Ms in this recipe.  Get crazy! Or just use all regular. The chocolate chips?  Just your regular semi-sweet version.  I want to try these with white chocolate chips next!

Bake time! That’s right, no dough chilling for this recipe.  The dough is quite manageable as is.  However, should you bake these cookies with a thinner peanut butter or on a particularly humid day, be sure to chill for up to 30 minutes in the refrigerator.  Cookie dough can be testy. Go by how your dough feels. If it’s too sticky, chill for 30 minutes. If not, just bake.

Roll into balls – about 2 Tablespoons of dough each (1 ounce – standard large cookie scoop).  Some of mine ended up being a tad smaller than 1 ounce to get 2.5 dozen cookies.  Really, you may roll the dough between 1.5 – 2 Tbsp each. I pressed a few mini M&Ms and chocolate chips into the tops of the balls before they baked.  To make them look pretty, of course. Bake for a precise 9-10 minutes. Do not overbake. The cookies will appear undone when you remove them from the oven. That is OK, I promise.  The cookies will firm up as they cool on the cookie sheet.  I allowed my batches to cool for 10 minutes on the sheet before transferring them to a cooling rack.

Quick and easy Soft-Baked Monster Cookies |

The cookies spread just slightly while baking, so you’ll need to press them down a bit with the back of a spoon once you remove them from the oven.  That’s what gives the cookies their crinkled tops.

Let’s discuss their texture. Wow.  I baked these on a Saturday and by Wednesday, they were STILL so soft.  Why did they last that long? I forgot I had one sitting around in a little baggie (whoops).  So, yes. These cookies remain exceptionally soft for days and days.  I also found that their peanut butter flavor is enhanced after day 1, too.  Just wait until you taste these!

The oats make them unbelievably chewy, the M&Ms give them a pop of color, and we obviously love the combination of chocolate chips and peanut butter.  And I love how thick they are!  Even after slightly pressing down after they come out of the oven, the cookies are still so thick and hearty.

Quick and easy Soft-Baked Monster Cookies |

In a world where there can never be too many peanut butter cookies, I’m happy to have a peanut butter oatmeal cookie I can use again and again.  Especially ones that took me a several batches to develop and perfect.  It was worth the wait!

Do you like oatmeal cookies? Peanut butter cookies?  Any favorite recipes I need to try?

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Soft-Baked Monster Cookies

The best monster cookies ever.

Yield: 2.5 dozen


  • 1/2 cup (1 stick or 115g) salted butter, softened to room temperature*
  • 1/2 cup (100g) light brown sugar
  • 1/4 cup (50g) sugar
  • 3/4 cup (185g) creamy peanut butter
  • 1 large egg
  • 1 teaspoon vanilla extract
  • 1/2 teaspoon baking soda
  • 1 and 1/4 cups (160g) all purpose flour (are you measuring flour the correct way?)
  • 1/2 cup (40g) quick oats*
  • 3/4 cup (150g) M&Ms (any size or variety)
  • 1/2 cup (90g) semi-sweet chocolate chips


Preheat oven to 350F degrees. Line baking sheet with parchment paper or silicone baking mat.

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 overmix. Fold in the quick oats, M&Ms, and chocolate chips. If the dough is very soft and unmanageable by hand, chill the dough for 30 minutes before rolling.

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 9-10 minutes - do not bake past 10 minutes. The cookies will appear undone. I too mine out at 9 minutes, 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. Store cookies covered at room temperature for up to 1 week. Cookies freeze well.

*You may use unsalted butter in this recipe. If so, add 1/4 tsp salt with the flour.

*Please use quick oats in this recipe. You need the slightly finer texture from the quick oats in order to give the cookies a more uniform texture. Quick oats will act more as a binder in this recipe than whole oats would, since the consistency is more powdery and the oats are smaller in size.

© Sally’s Baking Addiction. All images & content are copyright protected. Please do not use my images without prior permission. If you want to republish this recipe, please re-write the recipe in your own words, or link back to this post for the recipe.


Let’s talk peanut butter & oats.  And see where today’s recipe came from!

Today’s cookies are based off of my Soft-Baked Peanut Butter Lovers Cookies & Rolo-Stuffed Peanut Butter Cookies, among others.  These cookies are the same peanut butter cookie base, which is my go-to peanut butter cookie recipe.  These cookies do not have oats in them. I tried for weeks and weeks to develop a NEW peanut butter cookie with oats, with terrible results.  Then, I came back to my go-to peanut butter cookie recipe and added oats (with a few other slight changes).  Simple as that!


Soft-Baked Peanut Butter Lovers Cookie

Soft-Baked, thick, & chewy Peanut Butter Lovers Cookies. Filled with all of your peanut butter favorites!-2


Rolo-Stuffed Peanut Butter Cookies

Peanut Butter Rolo Cookies





295 Responses to “Soft-Baked Monster Cookies.”

  1. #
    Alinaposted November 12, 2013 at 10:48 am

    Hey, Sally!
    Last time I made these cookies they turned out AWESOME! But, it was back in Spain, now I tryed to make them in Russia, and I guess the flour is different. Anyway, they don’ melt) The dough is kind of crumled, and the cookies melt just a little bit, they look more like a ball, than a cookie) And when done, they fall apart) I only baked half of what I have and I still have some dough left, do you think you can save me and the cookies? What should I add? Butter? An egg? Milk may be?


  2. #
    marwaposted November 17, 2013 at 3:10 am

    Its amazing u rock .. :)).my kids really loves your cookies


  3. #
    siobhan slatteryposted November 17, 2013 at 9:14 am

    I love peanut butter, but my family doesn’t! Is there any substitutions? Perhaps nutella?


  4. #
    Mielissaposted November 18, 2013 at 2:37 pm

    Here is a nice variation that I made just for fun:

    Using a mini muffin pan, place cookie dough into the bottom of each well. Then lightly press a miniature Reese’s Cup into the top of each piece of cookie dough. Place some M&Ms in the top of the cookie dough. Bake as usual, and the Reese’s Cup will melt slightly. Let the cookies cool before removing.


    • Sallyreplied on November 18th, 2013 at 3:51 pm

      SUCH a fun idea! I have to try that. Thanks for sharing!


  5. #
    Kimberli Beanposted December 11, 2013 at 10:46 am

    I’m very excited to try your monster cookies! I’ve been looking for the perfect recipe to suit both my hubby and I – I love oats and he doesn’t – so I’ve been searching for a recipe that has some oats but not too many that he turns his nose up! This looks like the perfect one! I’m also looking forward to making them into jar cookies to give as gifts this year with my homemade vanilla! Thanks for the yummy recipe!!


    • Sallyreplied on December 11th, 2013 at 11:46 am

      Kimberli – I’m so glad you found this recipe! They aren’t “oat-y” at all. Just extremely peanut buttery. I think you’ll both love them!

      I’ve never tried them as jar cookies, but I have no doubt it would be wonderful. I have to make homemade vanilla sometime!


      • Kimberli Beanreplied on December 11th, 2013 at 12:01 pm

        I just made a batch and we both love them! I will be sure to give you credit on my jar directions, so everyone I give them to can visit your blog to find more yummy recipes!!

        • Sallyreplied on December 11th, 2013 at 12:13 pm

          Wonderful! Thanks Kimberli. :) Happy holidays!

  6. #
    Sandraposted December 20, 2013 at 1:35 pm

    I have tried these and wow.. I was amazed!!!! This was the first time I ever made cookies (I am new in the kitchen) and I was so scared that something would go wrong as it sometimes does with cakes.. but these.. I am speechless, everything turned out so great! They are so easy to make and yet one of the best cookies I have ever tasted, seriously…

    I am making these again for Christmas.

    Thanks a lot!


    • Sallyreplied on December 20th, 2013 at 2:38 pm

      What a compliment! Thanks so much Sandra, happy you love them! Merry Christmas.


  7. #
    Jennifer Jordanposted December 21, 2013 at 9:19 pm

    I just lover your web site! I don’t have time to develop recipes and I thank you for that. I have a home based cookie business. I primarily specialize in iced cut out cookies. They taste like soft graham crackers. Your website is my go to for extra special cookies!
    I just popped in the oven the magic cookie bars. Now I am making the monster cookies. I have graham crumbs left and butterscotch chips. Guess where they are going?? You probably did! Into the monster cookie dough. Thanks again! Congratulations on you upcoming wedding! Merry Christmas!


    • Sallyreplied on December 22nd, 2013 at 1:48 pm

      Hi Jennifer! I’m so glad you are loving my website. Your monster cookies are going to be SO good with some butterscotch chips and graham cracker crumbs! Thanks for the congrats, I appreciate it. Merry Christmas to you as well!


  8. #
    Christineposted December 22, 2013 at 2:32 pm

    My first batch just came out of the oven….OH MAH GEE….amazing. I only had 1/2 c. peanut butter so I used an additional 1/4 of cookie butter instead. Then 1/2 c. M&M’s with 1/4 c. dark chocolate chips, 1/4 cup peanut butter chips and 1/4 cup white chocolate chips. It almost tastes like peanut butter cheesecake. They are simply lovely…adore!!!!


    • Sallyreplied on December 22nd, 2013 at 3:05 pm

      Ok your version sounds incredible Christine!


      • Christinereplied on December 22nd, 2013 at 3:26 pm

        They are…thanks to you!

        I am getting ready to bake those brown sugar cookies you just posted….

  9. #
    merleposted December 30, 2013 at 5:41 pm

    Just wanted to let you know I made these gluten free by subbing in Better Batter flour – and they came out great…everyone loves them!! Thank you :)


    • Sallyreplied on December 31st, 2013 at 10:44 am

      Thanks for letting me know!


  10. #
    Deeposted January 5, 2014 at 7:18 pm

    Just made them…didn’t see the dough needed to be chilled for 30 minutes!
    PSH, no matter – these are amazing cookies!!!
    Thank you & God Bless!


  11. #
    JennyMooreposted January 6, 2014 at 11:28 am

    These were soooo yummo!! A new favorite for my family. It is everything we like in a cookie. Thank you so much for putting so much work into a great recipe!


  12. #
    Emily Quinnposted January 20, 2014 at 1:56 pm

    Can I leave the dough in the fridge overnight?


    • Sallyreplied on January 20th, 2014 at 6:22 pm

      You sure can. Cover the dough tightly and chill overnight. After that long of a time, the dough will be rather hard and stiff, so be sure to let it sit out for about 15 minutes before rolling into balls.


  13. #
    Sarahposted January 21, 2014 at 4:57 pm

    Have you ever tried rolled oats chopped in a vitamix instead of quick oats? Not that these cookies could ever be considered “healthy” despite their amazingness, but the glycemic index of rolled oats is almost 1/3 that of quick oats and they provide much more nutritional value. I’m not a big baker but I’ve tried this in a couple oatmeal cookie recipes and it usually works like a charm. Thanks for the awesome recipe…I’m having a little one in about a month and this was my go-to treat during maternity leave with my daughter. I’d much rather make my own than buy from the store!


    • Sallyreplied on January 21st, 2014 at 5:05 pm

      I often make quick oats from whole oats in my food processor, yes. Much easier than having two large containers of both oats in the pantry.


  14. #
    Nicoleposted February 3, 2014 at 10:53 am

    Hi Sally,

    I made these cookies last night for the nurses that are helping my LPN class with our final clinical rotation (2 more days!!). I’ve been baking for years but always find something off or lacking (in my opinion, no one elses). I love your recipes and know that you would only put the best of the best on your blog…so I made these…followed each letter of the directions…I even weighed my ingredients as opposed to measuring…and all I can say is WOW!

    I ate one because…well because…and they were awesome!! The nurses are going to devour these.

    I think I will never measure dry ingredients ever again…only weigh them!

    Thanks for sharing your recipes and your passion for baking!



    • Sallyreplied on February 3rd, 2014 at 11:03 am

      Great, Nicole! I’m so glad you made these cookies and I just know all the nurses will love them too. As I’ve learned over the years, weighing is certainly imperative!


  15. #
    Debposted February 7, 2014 at 2:28 pm

    I double this all the time and end up putting 5 add ins at 1/2 cup each. I use chocolate and/ or peanut butter chips, m&ms, Reese’s pieces, skor bar or Heath bits, and a new favorite…Kraft (I think) makes CARAMEL bits. They add a wonderful chew to the bites that they inhabit. I think I will try the idea from the reader who used a combo of cookie butter and peanut butter.


  16. #
    Ciara H.posted February 12, 2014 at 9:56 pm

    Sally. I just have to tell you what a hit these cookies have been in my house. I’m AMAZED at the texture. It’s is so originial and I absolutely love it! I will have to play with this to see what other recipes I can come up with!
    My husband is in pilot training and these cookies have been a favorite at quite a few events! Thanks for a great recipe!!


    • Sallyreplied on February 13th, 2014 at 9:14 am

      This comment made my morning. I think I know what cookies I want to make today on our snow day, Ciara!


  17. #
    Eleniposted February 22, 2014 at 10:28 am

    These were great! I made them last weekend when I was at a loss as to what to make when my original baking plans fell through. These were fast, easy and delicious! Everyone enjoyed them, they were gone in no time!
    Thanks for sharing these!


  18. #
    Dianeposted February 23, 2014 at 2:44 am

    Can’t wait to try these they look so yummy! One question, I’ve been into making my cookies larger these days (actually weigh them each at 2.5 ounces), would I need to increase the baking time? i would still be using the “tall” cookie dough trick. Thanks so much for all of the awesome cookie recipes. Can’t wait to wow my coworkers!


    • Sallyreplied on February 23rd, 2014 at 10:34 am

      I would still make sure your cookie dough balls are nice and tall, yes. I’m unsure of the exact baking time, but it will surely be a few minutes longer. Enjoy, Diane!


  19. #
    Rebekahposted March 2, 2014 at 10:05 pm

    Dear Sally, I have decided after making and baking many of your recipes that we need to be friends. Lol I find myself always checking with your website for “inspiration” or ways to help my create my inspiration dessert of the moment. (Is there really any need for other food groups??!) My newest experiment was the “monster cookies” omg….really Sally…really?!?!?!?! Was it necessary to post such an amazing recipe?!?! I have made a “batch” twice in 2 days….not helping the waistline. Lol anyway all this long winded – Ness to say…bravo! “Sallysbakingaddiction” has become my addiction!! I beg to to keep going lol!


    • Sallyreplied on March 3rd, 2014 at 9:18 am

      THanks for the wonderful report back, Rebekah. Made my morning! I simply love these cookies. And if you love dessert as much as I do, we are certainly friends!


  20. #
    Rebekahposted March 2, 2014 at 10:07 pm

    PS. White chocolate chips are my only add in….*heavenly sigh*


  21. #
    SAO'Dposted March 11, 2014 at 12:18 pm

    Quick question: I’m not seeing an acidic ingredient here, so why baking soda and not baking powder?


    • SAO'Dreplied on March 11th, 2014 at 12:20 pm

      Also: ALT+0176 is the degree (°) sign


    • Sallyreplied on March 11th, 2014 at 12:58 pm

      Brown sugar has a slightly acidic pH.


      • SAO'Dreplied on March 11th, 2014 at 3:40 pm

        Did not know that
        Unsweetened cocoa powder is usually the secret hidden acid, so wasn’t sure if the chocolate chips were sufficient

  22. #
    Jennifer Bposted March 12, 2014 at 1:13 pm

    Made these last night..I have a new go-to cookie! :D So soft, we all just loved them! Thanks!


  23. #
    Joanneposted March 13, 2014 at 10:59 pm

    Awesome!!!! My daughter made these tonight for “PI” day in her Algebra class tomorrow but I am not sure if they will make it till tomorrow!! Thank you.


    • Sallyreplied on March 14th, 2014 at 10:10 am

      A perfect treat to celebrate Pi Day, Joanne! Thanks for reporting back about them. These cookies are always a hit!


  24. #
    Cristinposted March 17, 2014 at 6:59 pm

    I have these in the oven right now – I can’t wait to see how they turn out. I like your idea of using peanut butter M&M’s…sounds dangerous.

    This recipe should be awesome. Thanks for all the detailed instructions as well – they really do help when you’re just a casual baker at home. Thanks again :)


    • Sallyreplied on March 17th, 2014 at 9:48 pm

      Thanks Cristin! I have a feeling you’ll love these. Thanks for trying them!


  25. #
    Juliaposted March 19, 2014 at 8:42 am

    I tried this recipe once, using about 100 grams of sugar, but they were really too sweet for me :( I think I would be fine with no more than 50-60gr, but I’m afraid the texture would change – with 100gr sugar they already weren’t very soft and chewy, more like regular cookies. What do you think? Any suggestions?
    Thank you!


    • Sallyreplied on March 19th, 2014 at 10:11 am

      There is a total of 150g of sugar. Are you using enough peanut butter? Usually that tones down the sweetness. If you want to drastically reduce the sugar, you can go with 75g of light brown sugar. And skip the white sugar altogether.


      • Juliareplied on March 19th, 2014 at 12:38 pm

        I used the indicated quantity for all the ingredients but the sugar, which I reduced to 100gr because I knew that 150gr would have been too much for me, but I still found them too sweet.
        I will try with 75gr brown sugar :) I love pb+chocolate+oats, I hope I can adapt this recipe to my taste!
        Thank you!

  26. #
    Hannaposted March 28, 2014 at 7:08 pm

    These. Are. AMAZING. Wow. I love love love them. Next time I make them, I’m going to sub in Reese’s Pieces for half of the M&Ms… I’m a peanut butter addict! I also prefer mini M&Ms to the regular size ones.

    I made this recipe to help fulfill one of the goals on my list- to try fifteen new dessert recipes. This is my favorite recipe by far! Thank you so much!


  27. #
    sonalposted April 3, 2014 at 10:38 am

    any egg replacement? say banana/yogurt? Thanks


  28. #
    BAYLEEOKposted April 3, 2014 at 11:46 am



  29. #
    sonalposted April 3, 2014 at 3:00 pm

    thanks:-) could u u pls recommend an oats based egg less recipe


  30. #
    Stephanie Grinwaldposted April 13, 2014 at 10:40 pm

    I made a test batch of these today, as I am planning to make them to bring to my family’s Easter gathering. I used Easter colored M&Ms and they were delicious and adorable! I can’t wait for my family to try them when I make them again this weekend. Thanks for such an easy and delicious recipe!!



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