Monster Cookies: Best Ever Recipe

If Halloween had a cookie mascot, it would be Monster Cookies. Besides having the name to fit the part (what better time for monsters than Halloween?) Monster Cookies are loaded with chocolate and peanut butter candies, the prize flavors of the trick-or-treat assortment.
Best Ever Monster Cookies: PERFECTION.

Back in the glory days of trick-or-treating, my sisters and I would spread our haul of candy on the carpet before us, sort it into piles based on personal priority, then commence the Great Halloween Candy Swap. Our living room was a mini-incubator for the free market at its finest. While my sisters opted for anything sour or fruity, I was—and still am—all about the chocolate and peanut butter.

I’m a chocolate + peanut butter lover to the core, and I loaded these Monster Cookies with both flavors. For the unfamiliar, a Monster Cookie is a peanut butter oatmeal cookie that is packed with yummy mix-ins, most traditionally M&M candies and chocolate chips. After experimentation, I am pleased to report that I have created the Ultimate Best Ever Blow-Your-Mind Monster Cookies. Pin this recipe now friends—this is the only Monster Cookie recipe you will ever need.

Best Ever Monster Cookies: PERFECTION.

That statement is a total superlative, and I’m standing by it.

Best Ever Monster Cookies

Our Monster Cookies begin with the softest, fluffiest peanut butter oatmeal cookie recipe I have ever created. Honestly, we could leave out all of the mix-ins, and we would still have a fabulous peanut butter oatmeal cookie. This is Halloween, however, candy is a must. Let’s packed our perfect peanut butter-oatmeal base with semi-sweet chocolate chips, dark chocolate M&Ms, and (for even more peanut butter flavor) peanut butter chips. Double the peanut butter, double the chocolate, double the delectability.

Don’t even pretend you are going to eat just one. Monster Cookies are not single-serving territory. I recommend pouring an extra large glass of milk to keep pace, these Monster Cookies are that outstanding. Plus look how little and fun they are! Their cuteness alone is reason enough to go back for more.
Best Ever Monster Cookies: PERFECTION.

As I shared with my Peanut Butter Cake with Chocolate Chips, when it comes to chocolate and peanut butter, I am loud and proud about flavor, and these Monster Cookies are no exception. Though I chose dark chocolate M&Ms, feel free to pick your favorite M&M flavor (or use a mix!)

Monster Cookies are also a tasty vehicle for any extra Halloween candy you have on hand. Try swapping in chopped Reeses, Twix, Hershey bars, or Butterfingers. The amazingly soft and fluffy peanut butter oatmeal Monster Cookie base is a delightful canvas for your candy favorites.
Best Ever Monster Cookies: PERFECTION.

Some of us may be too old to go knocking door to door on Halloween, but that doesn’t mean we shouldn’t treat ourselves. Let’s start with a big batch of softy, chewy Monster Cookies. No tricking here friends—these are the best Monster Cookies I have ever tasted, and I’d bet my entire stash of peanut butter and chocolate that they will be yours too.

My candy is on the line! Give these Monster Cookies a try.

PSST! Have you entered my Avocado All Star Giveaway yet? Click here to for your chance to win an avocado-riffic prize pack.

Monster Cookies

Best Ever Monster Cookie Recipe: Soft, fluffy peanut butter oatmeal cookies loaded with chocolate chips, M&M candies, and peanut butter chips. Feel free to sub in your favorite candy to make them your own and don't be surprised when they disappear!

Yield: 36-40 small (2-inch) cookies

Prep Time: 20 minutes

Cook Time: 10 minutes

Total Time: 30 minutes


  • 1/2 cup (1 stick) unsalted butter, softened
  • 3/4 cup firmly packed dark brown sugar
  • 1/4 cup granulated sugar
  • 1/2 cup creamy peanut butter
  • 1 large egg, at room temperature
  • 1 teaspoon vanilla extract
  • 1/2 cup + 2 tablespoons white whole wheat flour
  • 1/2 cup all purpose flour
  • 1/2 teaspoon baking soda
  • 1/4 teaspoon kosher salt
  • 1 cup old fashioned rolled oats
  • 3/4 cup M&Ms (plain, dark chocolate, or any kind you like)
  • 1/2 cup semi-sweet chocolate chips
  • 1/2 cup peanut butter chips


  1. Place rack in center of oven and preheat to 350ºF.
  2. In a large mixing bowl, cream butter, brown sugar, and granulated sugar until light and fluffy, about 3 minutes. Add peanut butter and beat until fluffy again, about 2 minutes. Beat in egg and vanilla until combined.
  3. In a separate bowl, stir together the white whole wheat flour, all purpose flour, baking soda, and salt. With the mixer on low, gradually beat the flour mixture into the peanut butter mixture until fully combined. Slowly beat in the oats. By hand, stir in the M&Ms, chocolate chips, and peanut butter chips. If time allows, chill dough for 30 minutes or overnight.
  4. Drop dough by rounded teaspoons onto a cookie sheet lined with parchment paper or a silpat mat (or leave cookie sheet ungreased.) Bake for 10 minutes until lightly golden brown (cookies may appear underdone). Let rest on cookie sheet for 5 minutes, then transfer to a wire rack to cool. Serve with a big glass of cold milk.

Store leftover Monster Cookies in an airtight container for up to 1 week.

64 Responses to “Monster Cookies: Best Ever Recipe”

  1. Anne [A Squared] — October 28, 2013 @ 8:11 am (#)

    Monster cookies are SO good! Love that you snuck whole wheat flour in here too.

  2. Zainab — October 28, 2013 @ 8:21 am (#)

    Monster cookies are always so good. I can’t meant to try these!!

  3. Luv What You Do — October 28, 2013 @ 8:40 am (#)

    I have never made monster cookies but they always look so incredible! I am pinning this recipe for sure!

  4. Ashley — October 28, 2013 @ 8:48 am (#)

    haha my sister and I did the exact same thing as kids. She liked nerds and sour patch kids and I was always about the chocolate/peanut butter combo. And we also clearly blasted halloween music while doing this – monster mash anyone??

    I love these cookies – I haven’t made monster cookies in far far too long.

    • Erin Clarke — October 29th, 2013 @ 9:50 am

      Monster mash is totally in my head now Ashley! Love it :)

  5. Mary Frances @ The Sweet {Tooth} Lifw — October 28, 2013 @ 10:59 am (#)

    Me amnd my mom have said many times that monster cookies truly are the best cookies. Ever. I think it is the oats and MnMs. I’ve never made them with pb chips and will definitely throw those in next time. So true about single serving … haha, there is no such thing!

    • Erin Clarke — October 29th, 2013 @ 9:40 am

      Single serving = MYTH. Thanks Mary Frances!

  6. Rachel @ Bakerita — October 28, 2013 @ 12:14 pm (#)

    Well, you had me at chocolate and peanut butter! These look amazing, and since I haven’t made monster cookies in ages, they are totally going on the “to-make” list.

    • Erin Clarke — October 29th, 2013 @ 9:40 am

      Rachel, I hadn’t baked monster cookies in forever, and they totally hit the spot. I hope they do for you too!

  7. Willow @ Will Cook For Friends — October 28, 2013 @ 12:16 pm (#)

    Okay, I have a confession… I never really jumped on the M&M’s-in-a-cookie band wagon… but I think that is all about to change. I was all about the peanut butter and chocolate as a kid, too (and still am!), and these cookies sound over-the-top in the best possible way. And they are so cute and tiny! I would eat a dozen without thinking twice. Nom!

  8. consuelohoneyandfigs — October 28, 2013 @ 1:43 pm (#)

    I love how fun these look and I’m definitely a sucker for the pb + chocolate + oats combo, but it’s super dangerous for me to have m&m’s around, because I always eat them all before putting them in the cookies oooOOooops. They’re so yummy, it’s impossible to stop at one ;)

    • Erin Clarke — October 29th, 2013 @ 9:37 am

      I must confess…while I had half a bag of M&Ms leftover after baking these, that stash didn’t last long. They are just so easy to snitch!

  9. Nora (Buttercream Fanatic) — October 28, 2013 @ 1:44 pm (#)

    I love a good monster cookie! I was, and still am, only in the Halloween spirit for the pb & chocolate candy (Reese’s were like hitting the jackpot, let’s face it), but now that I am old enough to buy my own and bake them into cookies, that Halloween happiness can last year round.

    • Erin Clarke — October 29th, 2013 @ 9:37 am

      Reeses = MONEY! And it’s true, we can buy candy all year, but Halloween seems like such a fun excuse. Power of being a grown up!

  10. bakerbynature — October 28, 2013 @ 2:18 pm (#)

    Monster cookies kind of own my heart! You’re sending some my way right?!

  11. Dixya @ Food, Pleasure, and Health — October 28, 2013 @ 2:19 pm (#)

    I am not too crazy about sweet and sour variety either. If we were sisters, it would not have ended well :P

    • Erin Clarke — October 29th, 2013 @ 9:36 am

      An epic battle for the ages! We’d have to do twice the trick or treating, just to make sure we both walked away with a satisfactory stash :)

  12. Maggie @ A Bitchin' Kitchen — October 28, 2013 @ 4:35 pm (#)

    These look awesome! Monster cookies are one of my favorites. In my experience they’re really good for shipping during the holiday season too since they are sturdy and stay nice and chewy for a few days!

  13. Julie @ Table for Two — October 28, 2013 @ 8:48 pm (#)

    I love monster cookies! I actually can’t believe I don’t even have a recipe on my blog for it. They’re definitely one of my absolute favorite cookies that remind me of childhood! I remember they were all I wanted to make. Yours looks fabulous!

  14. Nicole @ Young, Broke and Hungry — October 28, 2013 @ 10:50 pm (#)

    Halloween is made for monster cookies! I like to throw every candy I can into this dough and call it supper.

    • Erin Clarke — October 29th, 2013 @ 9:35 am

      I like your style Nicole. Sounds like the dinner of champions!

  15. Angie@Angie's Recipes — October 29, 2013 @ 7:35 am (#)

    Who doesn’t love M&Ms? These monster cookies look awesome!

    • Erin Clarke — October 29th, 2013 @ 9:35 am

      AGREE!!! Especially the dark chocolate ones (my personal fave.) Thanks Angie!

  16. Audra | The Baker Chick — October 29, 2013 @ 7:37 am (#)

    I LOVE monster cookies! They are so easy, fun and adaptable. These are perfect for Halloween!!!

    • Erin Clarke — October 29th, 2013 @ 9:34 am

      Me too Audra!! Whatever your mood, monster cookies are here to save the day.

  17. tanya — October 29, 2013 @ 8:21 am (#)

    Well I know what I’m doing with our left over Halloween candy!! These are wonderful Erin! Pinning for Friday!

    • Erin Clarke — October 29th, 2013 @ 9:33 am

      Thanks Tanya! Saving leftover Halloween candy one cookie at a time :)

  18. Cate @ Chez CateyLou — October 29, 2013 @ 9:27 am (#)

    What a great way to use up Halloween candy! Plus I’m a sucker for anything with peanut butter chips – I love those little things! These look so good

    • Erin Clarke — October 29th, 2013 @ 9:33 am

      Same Cate! PB chips just make the world a better place.

  19. Averie @ Averie Cooks — October 29, 2013 @ 11:51 am (#)

    I love Monster cookies. The texture, the oats, the M&Ms! Yes! :)

    • Erin Clarke — October 29th, 2013 @ 3:42 pm

      ME TOO Averie. You got it–monster cookies really are the total package!

      • Averie @ Averie Cooks — October 29th, 2013 @ 3:45 pm

        Oh and I had pinned them earlier and then I went to FG and they’re front and center – these babies are the hot ticket today :)

        • Erin Clarke — October 29th, 2013 @ 4:43 pm

          WHOO HOO! I didn’t even know they’d been published on FG yet, so this totally makes my day! Thanks so much for telling me Averie (and for pinning them too). You are simply the best :-D

  20. Melanie @ Carmel Moments — October 30, 2013 @ 7:44 am (#)

    They look oh so good. I’m sure my kids would love me forever if I made them these. Well, maybe not forever but at least the rest of the day. ;)

    • Erin Clarke — October 30th, 2013 @ 9:35 am

      Melanie, I think your kids would love these! Mostly because my husband does and he’s a kid at heart ;-) Thanks so much and hope you all enjoy!

  21. Kelly Senyei | Just a Taste — October 30, 2013 @ 9:39 am (#)

    Monster Cookies are one of my all-time favorite desserts! I’ve never made them with peanut butter chips so I can’t wait to try your version!

    • Erin Clarke — October 30th, 2013 @ 10:13 am

      If you love peanut butter, you will love the PB chip addition Kelly. It gives the cookies an extra PB boost that I find totally irresistable!

  22. Natalie @ Tastes Lovely — October 30, 2013 @ 10:49 am (#)

    Oh. My. Yum! These cookies look delicious! Fingers crossed the trick-or-treaters leave me enough M&M’s so I can make these this weekend.

    And thanks for commenting on my blog. Now I’ve found yours and I love it! Adding you to my reader. Can’t wait to see what you make next : )

    • Erin Clarke — October 30th, 2013 @ 12:29 pm

      You are such a doll, and I’m so glad I found your blog too! Thanks a million Natalie!
      RE: M&M leftovers <—hide ’em at the bottom of the bowl ;-)

      • Natalie @ Tastes Lovely — October 30th, 2013 @ 12:44 pm

        Now THAT is a good idea. Might hide a little of all the candy while I’m at it, don’t tell anyone ; )

  23. Jessica @ A Kitchen Addiction — October 30, 2013 @ 11:56 am (#)

    Monster cookies are my absolute favorite cookies! Can’t wait to try your version!

    • Erin Clarke — October 30th, 2013 @ 12:28 pm

      Thanks Jessica!!!! I was obviously way excited about them, lol. If you give them a try, I’d love to hear what you think! If they are your fave, you’ll be a great judge :)

  24. Georgia | The Comfort of Cooking — October 30, 2013 @ 1:39 pm (#)

    Oh my goodness, look at these gorgeous little colorful gems! You’ve totally taken me back with these cookies, Erin. They’re dangerously easy, so I’ve gotta give them a go!

    • Erin Clarke — October 30th, 2013 @ 4:13 pm

      Proceed with caution Georgia: once I started eating them, I couldn’t stop!

  25. Pamela @ Brooklyn Farm Girl — October 30, 2013 @ 4:17 pm (#)

    These monster cookies look perfect, I love how fun they are. Definitely on the list of sweets to make!

    • Erin Clarke — October 30th, 2013 @ 7:01 pm

      Thanks so much Pamela! The colorful M&Ms seem to brighten everything up. Hope you enjoy :)

  26. Sarah@ Economist at Home — October 30, 2013 @ 4:20 pm (#)

    I NEVER make cookies but I think I’ll have to try these. I adore PB&C.

    Would it be inappropriate to steal my kid’s Halloween candy to make these? Or worse, hypocritical if I were to forbid candy but let him eat candy in a cookie? Ah, the great dilemmas in parenting…

    • Erin Clarke — October 30th, 2013 @ 7:00 pm

      Sarah, if you adore PB&C, these cookies have your name written all over them! Mega parental conflict. I think if you steal the candy, give your kiddos a cookie or two, then hide the rest for your personal midnight snack needs, everyone will walk away happy ;-)

  27. Taylor @ greens & chocolate — October 30, 2013 @ 8:52 pm (#)

    Ohhh how I wish I could go trick-or-treating tomorrow just to get candy for these cookies!! Guess I’ll be one of the crazies raiding the discounted Halloween candy!

    • Erin Clarke — October 30th, 2013 @ 11:27 pm

      Taylor, I am forever “one of the crazies” going after the clearance candy. Who doesn’t love a bargain?? Go for it girl!

  28. anecdotesandapples — October 30, 2013 @ 10:24 pm (#)

    Hi Erin! These cookies are loaded with all sorts of goodness! I would have a hard time not eating the entire batch! Thank you for sharing them with us!

    • Erin Clarke — October 30th, 2013 @ 11:27 pm

      Thanks so much Monet! And since these cookies are in honor of Halloween, I’d say eating the whole batch is complete acceptable ;-)

  29. Summer — October 31, 2013 @ 6:25 am (#)

    OMG! These are packed with goods. So delicious

    • Erin Clarke — November 1st, 2013 @ 12:32 am

      You got it Summer! That’s why I love monster cookies so much. I can cram in all of my favorite :)

  30. Rachel @thedessertchronicles — October 31, 2013 @ 5:17 pm (#)

    I have such great memories of candy sorting and swapping- maybe the best part of Halloween! These cookies look like perfection :-)

    • Erin Clarke — November 1st, 2013 @ 12:27 am

      I think the candy swap is a key part of childhood Rachel! Maybe that’s where we first learn negotiation skills? :)

  31. laurasmess — November 3, 2013 @ 12:09 am (#)

    I’ve never heard of a monster cookie. Clearly, I had a huge deficit in my early development (I need to remedy that now by eating as many of these cookies as possible, just so… well, I get a good idea as to how wonderful they are). One problem: peanut butter chips don’t exist in Australia *waaaah!*. Should I just omit them altogether or should I add something else? xx

    • Erin Clarke — November 3rd, 2013 @ 11:53 am

      Peanut butter chip tragedy! You need to come to the states and stock up ASAP Laura ;-) Feel free to swap out the PB chips for whatever mix ins you like: more chocolate chips, butterscotch chips, chopped candy bars, or if you want to add more PB flavor, chopped peanuts would be delicious too. That’s the beauty of monster cookies: they transform to fit your pantry!

  32. Pingback: 50+ Awesome Cookie Recipes » Three Loud Kids

  33. Pingback: Cookies, Cookies, Cookies! | Luv What You Do

  34. Pingback: Good Eats #3 | the murphmans

  35. Kelsey — November 1, 2014 @ 6:21 pm (#)

    I love this a lot

  36. Pingback: Halloween Candy Monster Cookies | KrausnicKitchen

  37. Pingback: Triple Chip Oatmeal Cookie Mix in a Jar |

Leave a Comment

NEVER MISS A RECIPE! Subscribe to have new posts delivered to your email inbox: