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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.
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!
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!
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!
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!
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
BOO! Chocolate Peanut Butter Bars
Milk Chocolate Stuffed Jack-O’-Lantern 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
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.
Ingredients
- 2 sticks (1 cup) salted butter, at room temperature
- 1 cup dark brown sugar
- 1/3 cup light brown sugar (or more dark brown)
- 2 large eggs, plus 1 egg yolk
- 1 tablespoon vanilla extract
- 2 cups all-purpose flour
- 2 teaspoons baking soda
- 2 teaspoons baking powder
- 1/2 teaspoon kosher salt
- 2 cups old fashioned oats
- 1 1/4 cups Halloween M&M’s
- 1 cup mini pretzel sticks, crushed
- 1 cup semi-sweet chocolate chips or chunks
- candy eyes
Instructions
- 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.
I’ve never been able to perfect a cookie recipe, but this one came out great! Wondering if I could go ahead and scoop out into balls and freeze so I could bake a few at random vs making them all tonight?!? Curious how that would work with oatmeal and pretzels-would they be mushy or still bake up good?!? May attempt!!
Hi Katelin,
So glad to hear that these cookies were enjoyed! Yes, I think they would be just fine to freeze! Hope you’re off to a great day! xx
Hi! We have a Halloween block party coming up, could this be made as a cookie cake? Would love to make these that way, to contribute to our cake walk event. I saw your other cookie cake recipes on here bake anywhere from 18-22 minutes. Could I try that with this recipe? Thanks!
Hi Holly,
So sorry, do you mean just my regular bar cookies? I’ve never made a cookie cake before and since I haven’t tested that with this recipe I’m not sure how it would turn out. I would follow this recipe:
https://www.halfbakedharvest.com/monster-oatmeal-chocolate-chip-cookie-bars/
I hope this helps, let me know if you give the recipe a try! xx
Whoops I meant the skillet cookies! That’s what I was going for. I ended up using the recipe as is except cut the leavening agents in half and baked for about 2 minutes and it came out great! Loved the recipe! Will definitely make again as regular cookies too!
Hey Holly,
Love it!!🤩 So glad to hear that this recipe was a hit, thanks so much for making it! xx
I am simply so glad that you have so many recipes! Hands down the best cooking website ever me and my mom love to bake together on this and we have such a good time. Our cookies came out a little thick?
-sam
Awe thanks so much Samantha!! So glad to hear you have been enjoying the recipes:) Next time, when you rotate the baking sheet, try banging them on the counter, that should help! xx
I made these cookies yesterday and they are delicious and adorable!! I added Reese’s Pieces to a few of the cookies and those are great as well.
Hi Jacqueline,
Yum!! Such a great idea to add the Reese’s Pieces! Thanks for making the recipe:) xx
The cookies were very good. I’m a sucker for anything with salty sweet flavors and they had a pleasant consistency to them, although the oatmeal in mine didn’t seem to cook all the way as it would normally do for an oatmeal cookie. I ran out of all-purpose flour and substituted a half cup with buckwheat flour (Ala David Lebovitz buckwheat chocolate chip cookies). It gave them a nice earthy undertone under all of the sweetness. I wonder if the cookies would be improved further by letting the dough sit in the fridge overnight before baking. Overall, it was a pretty good cookie, although I honestly probably wouldn’t make it a second time. Also, I’m a metric system kind of baker – and the measurements given seemed way off compared to the amount of cups needed for each ingredient. Admittedly, it also bothered me that we were using salted butter considering it gives less consistent results and the amount of salt in salted butter is extremely variable.
I feel like I have to take back what I said about the cookies. They definitely improve after sitting overnight (I probably ate them too soon out of the oven and didn’t let the dough sit long enough), but they were delicious! I keep looking for excuses to eat another. Also still stand by the buckwheat sub for a quarter of the flour. Although, I personally love the heartiness of buckwheat.
Thanks again for sharing Sarah!!
Hi Sarah,
Thanks so much for giving this recipe a try and sharing your feedback! So sorry to hear that you didn’t love them! What kind of oats did you use? I always use salted butter in my recipes, but you an certainly use unsalted:) xx
Mmm my son and I made these Halloween cookies today and they turned out so good! Loved by everyone in the family! Will definitely be making them again 😊
Hi Leanne,
Happy Sunday!!🎃 I am delighted to hear that this recipe was enjoyed, thanks for making it and sharing your feedback! xx
These look so fun! I’m going to make a batch today – planning to add 1/2 cup of crunchy PB. Can I bake 2 baking sheets at a time?
Hi Amber,
Thanks so much!! Sure, that is great! I hope you love the recipe, let me know how they turn out! 👻
Hi Tieghan – they turned out really well! I also added 1/4 cup of wheatgerm, and they were fantastic. A huge hit in our house and at an elementary school open house. I think these may be my new go-to monster cookies! Thank you for sharing your recipe. 🙂
Awesome!! So glad to hear this!!
Made these cookies and unfortunately won’t make again. My toddler likes them but to my husband and I, the cookies were really mealy and bland. I think if I added Reese’s pieces it would add more flavor. To save the batch I will be making ice cream sandwiches out of them!
Hi Ashley,
Thanks for giving this recipe a try and sharing your feedback, sorry to hear they were not enjoyed! Please let me know if there is anything that I can help with! xx
I made these today and they were so good! (I ate 2 haha!) They were so tasty and they are so cute with the candy eyes! Definitely will be making them again 🙂
Hi Sara,
Wonderful!! I am thrilled to hear that this recipe was enjoyed and truly appreciate you making it! Have a great weekend! 🍁🍂
I made the Halloween cookies today. They turned out great! Looking forward to making them again
Hey Beverly,
Happy Friday!! I am thrilled to hear that this recipe was a winner, thanks a bunch for making it! 👻
Yummy cookies. Does high altitude change your baking since you’re in CO? If so, is it possible for you to recommend adjustments for those who aren’t high altitude, i.e., adjusting the baking soda and powder? Always love your recipes though.
Thanks so much for trying the recipe Sherry! I always cook/bake as if I am at sea level, so you should be able to follow the recipes as written, that’s how I always intend for them to be! Let me know if you have any other questions:) xx
Amazing cookie! I reduced baking soda and powder by 1 tsp each per comments and did slightly flatten balls. I also used Reese’s pieces instead of M&Ms.
Hey Laurie,
Happy Wednesday!!👻 I truly appreciate you giving this recipe a try and sharing your feedback, I love to hear that it was enjoyed:)
I just read through the comments about how to make them flatter. No need to respond!
Thanks Laura, I hope this helps!!
Mine did not flatten out like the picture. Still very cute and delicious but curious if there is anything I could do differently?? I followed recipe exactly. Thanks!
Hi Laura,
Thanks so much for giving these cookies a try! Next time, you could gently flatten the dough with your hand before baking and then tap the baking sheet on the counter a few times while the cookies are baking. I hope this helps! xT
I made this recipe for a cookout this weekend following the directions exactly, and they were sooo good. I did press the dough down slightly after forming into balls and tapped the baking sheet down a couple times during baking. They came out flat like the pictures and super yummy. A huge hit! Will definitely make again and modify for Christmas
Hey Christy,
Awesome!! Thanks so much for making this recipe and sharing your feedback, I am thrilled to hear that it was enjoyed! xx
Hi Tieghan,
I usually refrigerate chocolate chip cookie dough before baking and they come out great. Would I be able to do the same for your monster cookie recipe?
Also do you think using crisco butter flavored would be okay? I also use crisco butter for my chocolate chip cookies so I was wondering if that would be okay for your recipe too.
Thank you so much
Bernice
Hi Berenice,
Sorry, I’ve never used crisco butter so I’m not sure on that one, if it’s something you like go for it! If you chill your dough the cookies won’t spread as much. But again, totally personal preference as to how you like the texture of your cookies! I hope you love this recipe:) xx
Hi Tieghan,
Thank you so much for sharing this recipe. I just made these cookies and they came out so perfect just as I imagined lol. I did use the crisco butter and since it is unsalted I added 1 1/2 teaspoon of salt and they came out so good and moist. Also there was no need to refrigerate this cookie dough. Thanks again! Can’t wait to make these again.
Hey Berenice,
Happy Monday! 👻 I am thrilled to hear that this recipe was a winner, thanks so much for making it! Happy Halloween! 🎃