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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.
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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
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.
Nutrition
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Did you make this recipe? Please rate & comment below.
They didn’t flatten and the oats tasted pretty raw. All the measurements were consistent. Very possible the powder or soda were expired but they just didn’t turn out right. I can tell they would have been delicious but they just didn’t work for me.
Hey Kelsey,
Thanks for giving this recipe a try, sorry to hear you had some issues! I would check to make sure all of your ingredients are fresh. Also, did you use old fashioned oats? Let me know how I can help! xx
Fair point to update my ingredients. I need to keep track of the expiration dates when i move them to airtight containers. I did use old fashioned oats. Are those different than rolled oats? I didn’t know that.
Nope, that’s correct, I was just making sure you didn’t use instant oats! I know it can be so hard keeping track of expiration dates, unfortunately those can make a break a baking recipe!! Hope you’re having a great day! xx
Love the cookies and my kids do too, but they never got as flat as yours, just slightly. I followed the recipe exactly.
Hi Shana,
Thanks for trying the recipe! Next time, remove the baking sheet while the cookies are baking and tap on the counter to help flatten the cookies! I hope this helps! xT
My 4 year old and I made these this afternoon. They were super easy and fun to make. I love the chewy texture.
Hey Kristen,
Awe, love to hear this!! Thanks so much for making these cookies! xTieghan
Had so much fun making these cookies with my 7 year old grandson. Very tasty, festive and fun!!!
Hi Lynette,
Happy Monday!🎃 I am thrilled to hear that this recipe was tasty for you, thanks a bunch for making it! xx
These are adorable and such fun to make! My 28 year old daughter and I whipped them up last night after dinner. They won’t last long, daughter already snagged some to take to her boyfriend tonight. I’ll put half the batch in the freezer! I love the oatmeal and pretzel additions – and the candy eyes are so cute! Unfortunately we could only find bloodshot candy eyes so had to go with those – will look for the eyelash ones earlier next year.
Hey Shelley,
Awe, thanks so much for your kind message and making these cookies! So glad to hear they were enjoyed. Lol I would love to see them with the bloodshot eyes! Happy Sunday! xx
Plan on making these, can I leave out the oatmeal? Do I have to adjust anything?
Thanks
Hi Mary,
I’ve not made these without the oats, I would try adding 1/3 cup of flour. I hope you love the recipe, please let me know if you give them a try! xx
So yummy and fun for my 4 yo and 2 yo. Thanks for the easy and festive recipe!
Hey Angie,
Happy Sunday! I am delighted to hear that this recipe was enjoyed, thanks so much for making it! xTieghan
I usually love all of HBH recipes, this one did not turn out well. They were ultra puffy and didn’t flatten and also tasted too strong of the baking soda or powder. I feel like something is off in the measurements above since it seems that most people have had the same issue with them flattening out.
Hi Kayla,
Thanks for trying these cookies, sorry to hear you had some issues. All of the measurements are correct. Were any of your ingredients expired? Let me know how I can help! xT
I think it’s the 2 teaspoons of baking powder.. or the 2nd egg. Just made these and mine turned out like puffy cake balls. Been in search of thin gooey crispy cookies and most recipes call for no baking powder, less baking soda, and 1 egg and 1 yolk. Not sure how anyone could get these to spread.
Huge fan of this blog though!! Just trying to figure out where this one recipe went wrong.
Just made these, very disappointed they didn’t flatten!
Hi there,
Thanks for trying these cookies, sorry to hear they didn’t flatten for you. Was there anything you adjusted in the recipe? A little more info would help me to better figure out what went wrong. xT
Delicious! I thought it was a bit too salty using the salted butter, 1/2 tsp of salt, plus for salt in the pretzel sticks so I think next time I might use unsalted butter.
Hey Virginia,
Wonderful! I love to hear that this recipe was enjoyed and appreciate you giving it a try! Have a great weekend!🍁
Just curious if anyone has tried this with gluten free flour? I am going to but with only a half of the recipe, just in case. I do really like your recipes, and they are so creative! Thank you for your hard work and all you do!
Hi Alene,
An equal amount of gluten free flour should work well for you! I hope you love the recipe! xx
I am not sure what I did wrong, but mine did not spread at all. They stayed thick round balls until a flattened them with a fork after around 6 mins of baking. They ended up quite thick and dense in the end. Still tasty given all the chocolate but definitely did not look like your picture. I think I may try less oats next time. Any other suggestions?
Hi Janna,
Thanks for giving the recipe a try, sorry to hear you had issues. Was there anything you adjusted in the recipe? Next time, try removing the baking sheet from the oven and tapping on the counter while the cookies are baking. I hope this helps! xx
These were yummy. I was hesitant to try bc of the comments about being too flat but these were amazing. Mine needed 1 extra minute to be perfectly crispy, otherwise made to the recipe exactly.
Hey Shannon,
Fantastic!! So glad to hear that you enjoyed this recipe, thanks so much for making it:) Happy Friday! xx
Hi Tieghan, do you have any tips on how you get your cookies thin, especially with the oats? Mine always seem to end up on the fluffier end.
Hey Aubrey,
Try pulling the cookies from the oven during the baking and tap the sheet pan on the counter, this should help to flatten them! I hope this helps! xT
Hi Tieghan Can you tell me how you added the eyelashes to the candy eyes? It is so cute and creative! I love them.
Thanks so much Ellen!! I bought the candy eyes like that:) Unfortunately, they are sold out, but here is the link:
https://shopstyle.it/l/bMsrL
Please let me know if you have any other questions! xT
So tasty, love the addition of the pretzels! The eyes w lashes are too cute, source?
I have eyes, can’t find the lashes.
Definitely will make again!
Hi Stephanie,
Here is the link, unfortunately they are currently sold out:
https://shopstyle.it/l/bMsrL
Please let me know if you have any other questions! x
hi tieghan- if I wanted to not use oats do I just add more flour? Or can I just omit the oats? Thanks!
Hi Brittany,
I’ve not tested this, but you could try adding 1/3 cup of flour. Let me know if you give this recipe a try, I hope you love it! xT