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Boooo! Halloween Monster Mash Cookies! Festive, easy, sweet, and gravely spooky! Homemade chocolate chip cookies, made with oats, pretzels pieces, plenty of chocolate chunks, spooky Halloween M&M’s, and crazy candy eyes. There’s nothing not to love about these sweet chocolate cookies with a little salty pretzel crunch. Each bite is slightly crisp on the edges but soft and gooey in the center with melted chocolate throughout.

Halloween Monster Mash Cookies |

Ahhh! I am so happy to share these! In all honesty, I’ve wanted to make these fun, super yummy cookies for months. Actually, since almost a year ago when I made my much loved Christmas Monster Cookies. It was then that I knew that Halloween Monster Cookies needed to follow.

I’m not sure which cookie I love more. Both are unique, special, and melt-in-your-mouth delicious.

I know, I’m such a dork, but nonetheless, I just love how fun Halloween can be!

I wanted to share them very early in the Halloween season. My hope is that you can bake them up for all of your Halloween needs. Parties, school functions, and even just as a fun cookie to bake on a random weekday. Whatever you bake them up for, they require almost no effort!

Halloween Monster Mash Cookies |

Spooky details

Start off by gathering all of your ingredients. You’ll need the basics: salted butter, dark and light brown sugar, flour, baking powder, baking soda, and salt – the usuals.

You’ll also need the stir-ins, they’re the most important element of these cookies. You’ll need old-fashioned oats, salted pretzel twists, semi-sweet or dark chocolate chunks, and candy eyes. Plus plenty of spooky Halloween M&M’s, which, of course, make these cookies.

Simply mix up the dough, bake each cookie off, and then enjoy!

Halloween Monster Mash Cookies |

We love to eat these cookies warm, just out of the oven. They’re just the right type of gooey delicious cookies to pull out, slightly cool, and indulge in.

One thing that’s important to note, is that these cookies do spread, so don’t stress on that. Because of this, they’re meant to have slightly crisp edges and perfectly soft gooey centers, just like in the photos. My favorite type of cookie. Everyone has really been loving these cookies, they’re definitely an Oslo favorite!

Halloween Monster Mash Cookies |

If you want a bit of a thicker cookie, simply omit the additional egg yolk and use only two eggs. As a result, this will give you a thicker cookie without as much spreading.

To get the M&M’s to really pop, I like to add in a few just before the cookies finish baking completely. This way each cookie has a bit of the festive M&M’s right on top.

Excited to see you all bake these up this month! What’s incredible about these cookies is just how easy they are. So have fun with them and enjoy every shamefully sinful spooky monster bite!

Halloween Monster Mash Cookies |

Looking for other Halloween cookies? Here are my favorites: 

“I put a Spell on You” Poison Apple Martini

Black Widow Peanut Butter Bars

Hocus Pocus Spellbook Brownies

Spooky Halloween Pretzels

BOO! Chocolate Peanut Butter Bars

Milk Chocolate Stuffed Jack-O’-Lantern Cookies

Black Cat Pumpkin Cupcakes

Roly Poly Pumpkin Cookies

Lastly, if you make these Halloween Monster Mash Cookies, be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! Looking through the photos of recipes you all have made is my favorite!


Halloween Monster Mash Cookies

Prep Time 20 minutes
Cook Time 15 minutes
Total Time 35 minutes
Servings: 20 cookies
Calories Per Serving: 311 kcal

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.



  • 1. Preheat the oven to 350° F. Line a baking sheet with parchment paper.
    2. In a bowl, beat together the butter, brown sugar, and vanilla until combined. Beat in the eggs and 1 egg yolk, 1 at a time, until combined. Add the flour, baking soda, baking powder, and salt. Beat in the oats.
    3. Fold in 1 cup of the M&M's, the pretzels, and chocolate chips.
    4. Roll the dough into 1/4 cup size balls. Place 3 inches apart on the prepared baking sheet.
    5. Bake for 8 minutes, then rotate the pan and bake another 2 minutes. Pull the pan out and push the remaining M&M's and candy eyes into the cookies. Bake 2-3 minutes. Remove from the oven and let the cookies cool on the baking sheet. They will continue to cook slightly as they sit on the baking sheet.
    6. Eat warm or let cool and store in an airtight container for up to 4 days. 
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Halloween Monster Mash Cookies |

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  1. 5 stars
    Instead of brown sugar, I used honey. And I used whole wheat flour. I also added coconut flakes, unsweetened, and instead of butter I used coconut oil. And they still turned out. AMAZING!!

    1. Hey Jacqueline,
      Wonderful! So glad to hear this recipe turned out for you, thanks for giving it a try! Happy Friday! xT

    1. Hey Brianna,
      I have not tested this, but I would add 1/3 cup of flour if you plan to omit the oats. Please let me know if you have any other questions, I hope you love this recipe! xT

  2. 5 stars
    Great cookies! Make both the Halloween & Christmas versions.
    Where can I find the candy eyes with eye lashes?
    Note to Canadian followers; the seasonal M&Ms are only available in the States.

  3. 5 stars
    Ok, so I made 100 of these bad boys the other night for my kids Halloween class parties and they were a HIT! Did they look exactly like the photos? Of course not! I didn’t expect them too since we all use different brands of ingredients. One thing to note that I think might help some people: If you are doubling the recipe like I did, there is no need to double the eggs! I forgot to do this on accident with my first batch, but they turned out so good I decided to do the same thing with my second batch.

    1. Hey Sarah,
      Amazing!! Thanks for the tip on doubling and love to hear that these cookies were such a hit! I appreciate you trying the recipe:) xT