Soft and Chewy Monster Cookies
Peanut butter oatmeal cookies packed with M&M’s and chocolate chips. These monster cookies are incredibly soft, chewy, thick, and so easy to make!
What Are Monster Cookies?
Say hello to one of my favorite cookie creations, these incredibly soft and chewy monster cookies! If you’ve never had a monster cookie, then I think you’ll adore these cookies that are jam-packed with tons of goodies.
Originally published in September of 2017, this is still the same delicious cookie recipe. However, I’ve updated this post with more step pictures, information, and better instructions so that you can easily whip up a batch of these cookies.
Bonus: you don’t even have to chill this cookie dough. That means you can be enjoying soft, warm cookies in about 30 minutes!
Monster cookies are essentially peanut butter oatmeal cookies with chocolate chips and M&M’s. It’s kind of like three different cookies all packed into one.
You can also make monster cookies different ways, like with milk chocolate chips or Reese’s Pieces instead of M&M’s. However you make them, they’re one of the most delicious cookie recipes you’ll ever try!
This is essentially a recipe for peanut butter oatmeal chocolate chip cookies. Can you say “yum?” Here’s what you’ll need to make these oatmeal monster cookies:
- All-Purpose Flour: The base of any good cookie recipe starts with some flour. Just make sure you spoon and level your flour into the measuring cup so you don’t end up with crumbly cookies.
- Baking Soda & Salt: The baking soda provides a little lift while the salt balances out the sweetness of the dough.
- Old-Fashioned Rolled Oats: I suggest sticking with old-fashioned rolls oats in these cookies because they make them chewier! Quick oats would probably be fine too, just keep in mind that they’re pressed thinner and won’t provide the same level of chewiness.
- Unsalted Butter: As always, I prefer to stick with unsalted butter in my cookie recipes. This allows you to control the amount of salt going into your cookies.
- Brown Sugar & Granulated Sugar: I love to use a mix of sugars in my cookies, the brown sugar adds flavor and moisture.
- Peanut Butter: It’s best to stick with a thicker, no-stir peanut butter like Jif or Skippy.
- Egg & Pure Vanilla Extract: There’s only one egg in this cookie dough and it helps to bind everything together. The vanilla extract adds a little extra flavor.
- M&M’s and Semi-Sweet Chocolate Chips: You can easily switch up the flavor of these cookies by using another baking chip, different kinds of M&M’s, and so on.
How To Make Monster Cookies
To make these monster cookies, you’ll start out by whisking together the flour, baking soda, and salt. Then, stir in the old-fashioned rolled oats until fully combined.
Next, you’ll cream together your butter, brown sugar, and granulated sugar for 1 to 2 minutes or until they’re well combined. Once the butter and sugar are thoroughly mixed together, mix in the peanut butter, egg, and vanilla extract. I also recommend stopping to scrape down the sides of your bowl, and mixing again to ensure that all of the wet ingredients are well combined.
Once you’ve mixed up the wet and dry ingredients, you’ll combine them and then stir in your chocolate chips and M&M’s. At this point, you can scoop the cookie dough onto baking sheets and bake the cookies or refrigerate/freeze it until you’re ready. I like to use a 1.5 tablespoon cookie scoop because it creates the perfect size cookies!
How do you make these cookies soft?
To create soft oatmeal M&M’s cookies, you want to avoid overbaking them. The tops will be set, but they will still be soft when you remove them from the oven. The cookies will continue to firm up from the residual heat of the baking sheet and as they cool.
Tip: Store the cookies in an airtight container with a slice of bread. This will help them stay soft for days!
Can you freeze them?
Yes! You can freeze the balls of cookie dough or baked peanut butter oatmeal chocolate chip cookies that have cooled completely for up to 3 months. You can bake frozen cookie dough balls for an additional 1 to 2 minutes, no need to thaw the cookie dough. For the baked cookies, you’ll want to thaw them to room temperature on the counter before serving.
How can you tell when the cookies are done?
The edges and tops of the cookies will look set and no longer doughy. I find that about 10 to 11 minutes at 350°F (177°C) is the perfect amount of time for these cookies.
- When measuring your flour, make sure to spoon it into the measuring cup and level it off with the back of a knife.
- Using a natural peanut butter where the oil separates will cause these cookies to spread more and turn out greasy. I suggest sticking with a thicker, no-stir peanut butter like Jif or Skippy.
- Make sure to stick with old-fashioned oats, this will create a much chewier oatmeal cookie!
- Feel free to swap out the semi-sweet chocolate chips for dark chocolate or milk chocolate chips and the M&M’s for Reese’s Pieces.
More Classic Cookie Recipes to Try!
- Peanut Butter Cookies
- Oatmeal Raisin Cookies
- Chocolate Chip Cookies
- Classic No-Bake Cookies
Soft and Chewy Monster Cookies
- 1 cup (125 grams) all-purpose flour , spooned & leveled
- 1 1/4 cups (125 grams) old-fashioned rolled oats
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 1/2 cup (115 grams) unsalted butter , softened
- 3/4 cup (150 grams) brown sugar , lightly packed
- 1/4 cup (50 grams) granulated sugar
- 1/2 cup (125 grams) creamy peanut butter
- 1 large egg , room temperature
- 1 teaspoon pure vanilla extract
- 3/4 cup (150 grams) M&M's
- 1/2 cup (95 grams) semi-sweet chocolate chips
- Preheat oven to 350°F (177°C). Line two large baking sheets with parchment paper or silicone baking mats and set aside.
- In a large mixing bowl, whisk together the flour, old-fashioned rolled oats, baking soda, and salt. Set aside.
- In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using a handheld mixer, cream together the butter, brown sugar, and granulated sugar for about 1-2 minutes or until well combined. Mix in the peanut butter, egg, and vanilla extract until fully combined, making sure to stop and scrape down the sides of the bowl as needed.
- Slowly mix in the dry ingredients until just combined. Add the M&M's and chocolate chips and gently fold them into the cookie dough.
- Using a 1.5 tablespoon cookie scoop, scoop balls of cookie dough onto the prepared baking sheets, making sure to leave a little room between each one.
- Bake in separate batches at 350°F (177°C) for 10-12 minutes or until the tops of the cookies are set. Remove from the oven and allow to cool on the baking sheet for 5-10 minutes, then transfer to a wire rack to cool completely.
These look delicious and worth trying! I look forward to baking these sometime soon I hope. Love how there’s so much positivity in your posts. There’s a lot of bloggers who exhibit judgmentalism and criticism on others choices, seemingly as a way of boosting the coolness or credibility of their posts but I find that very irksome (not to mention ethically questionable). You don’t do that – thank you! All the more reason I consider your blog to be number one. Kudos!
Thank you for the kind comment, Anna! I really do appreciate it! It means a lot that you consider my blog to be one of the top ones! 🙂
Does old fashioned peanut butter that needs to be stirred work in these cookies? I’ve found that with some recipes you have to use the hydrogenated kind or the oil separates out
It doesn’t work as well as a brand like Jif or Skippy. I would suggest using one that doesn’t need to be stirred in these cookies.
My whole family loved these cookies! Perfect combination of our three favorite cookie add-ins. Thank you again for another awesome recipe. 🙂
So happy to hear that everyone loved the cookies, Elizabeth! These cookies are one of my favorites 🙂
Can i freeze the dough for a week or two before baking?
Absolutely! You can scoop out the cookie dough into balls, place them on a baking sheet with parchment paper, and freeze them first (this helps to keep them from sticking together in a freezer bag/container). Then add the frozen balls of cookie dough to a freezer bag/container and store in the freezer until you’re ready to bake them. You can bake the cookie dough from frozen, just bake an additional 1-2 minutes if needed.
I made these this weekend for Valentine’s Day. I added the red, pink and white M&Ms to go with the holiday. They were a big hit! The old fashioned oats really do make a difference, my husband enjoyed the chewiness ? He joked and said we should call them Frankenstein’s ? Making these again very soon and I might add walnuts for an extra crunch!
Decided to make some monster cookies and this was the easier recipe. So far so good they in the oven and smelling awesome. I added a few extra m&ms and chocolate chips. Hope the little man likes them.
Hope you and your little one enjoy the cookies, Rebecca!
Can you use dalted butter
That would be fine, Sheila. I would reduce the salt in the recipe though and just use a pinch or maybe about 1/8 teaspoon instead.
I have been searching for a good Monster cookie for a long time. I’ve tried a few others, but I always find them hard and dry. I am so thankful I found your recipe! They are DELICIOUS! My whole family loves them. I love how soft they are. Thank you!
Thank you, Ashley! So glad you and your family loved the cookies!
Thank you so much for a simple, delicious recipe! My cookies turned out super soft and yummy!
So happy to hear that, Michelle!
My eleven year old made these today with two of her girlfriends. She is an experienced baker, and she said they were easy to make and they tasted good. Mom sampled one too! Good stuff! Thanks for a solid, easy recipe. Looking forward to trying other ones from your blog now 🙂
So glad to hear that, Jamie! I’d love to hear if you try any other recipes!
These cookies turned out perfectly! I baked 10 minutes and left on the pan for 6 or so. Perfectly soft with a little bit of crunch! So yummy. It made 25 cookies after some dough was eating by me and my munchkins! Nice recipe size so it doesnt go to waste and hopefully I dont eat a dozen! I didnt have enough MMs so I added vanilla chips til there was enough. Great chocolate to cookie distribution in the recipe! I put the MMs on top to make eyes and to reduce the puffiness. Super great recipe. It is bookmarked now.
Hi Danielle, can we replace egg with flax egg
I haven’t tried it, but I think it would be okay.
Oh my goodness. These cookies are my family’s new favorite. I have made 10 batches in the last two weeks! And haven’t had one go to waste. I added peanut butter m&ms and only a handful of regular m&ms, along with milk chocolate chips. They turned out amazing. Definitely a new staple dessert. Thanks!
So happy to hear that, Dinah!
These cookies sound amazing… I’m anxious to make them! I have some almond bark (for dipping) on hand… can I break it up and use it in these cookies? Or would it be too soft?
Thanks, Danielle, for all the great recipes.
Hi, Verna! Almond bark melts pretty easily, so I’m not sure that it would hold up well if you bake it in these cookies. I would suggest chocolate chips if you can use them.
Do you need to use a paddle attachment?
It works best if you’re using a stand mixer, but the whisk attachment would work too.
I followed the recipe exactly and still ended up with a crumbly mixture. What can I do to ensure that this won’t happen again? It was so crumbly, I could barely get them to form into a ball before baking.
Sorry you had trouble with the recipe, Caley. The cookie dough definitely shouldn’t be crumbly. Did you make any adjustments to the recipe and did you make sure to spoon and level your flour?
Hi! Your recipe looks good and simple to make. Can I use the same recipe to make bars instead of cookies?
Yes, absolutely! An 8-inch square pan may be a bit too small, an 11×7 or 9×13 pan may be better.
Hi there! Made these twice already. Once a normal batch, then a double one. My question, could i halve the sugar?thank you!!
You can cut down the sugar, but keep in mind that sugar helps cookies spread. If you reduce the sugar you may need to flatten the cookie dough before baking.
Hi there! Can we use crunchy peanut butter for this recipe? I wasn’t able to get my hands on creamy cause all the stores are empty!
Yes, that’s fine!
Where is the nutrition?
I’m not sure about the nutritional information, but you can plug everything into an online calculator to get an estimate.
Is it better to refrigerate the dough before baking?
For most of my cookies I recommend it, but I don’t find it necessary for this one.
Thank you! They came out great!!
I was craving these so bad but only had maple and brown sugar instant oatmeal, I used 4 packets and lowered the amounts of the other sugars enough to compensate and I was out of chocolate chips, BUT!!! They still turned out so so so good!! Thank you for a great recipe! (Even though I had to tweak it at my own fault… lol)
I followed the recipe exactly and they turned out horribly. They were extremely dry and stayed in a ball. I had to flatten them down after ten minutes of baking. Very dissappointing.
Sorry you had trouble with the recipe, Mary. Did you make sure to spoon and level your flour or did you happen to scoop it from the container. Too much flour can lead to cookies that don’t flatten and turn out dry.
Your cookies are freaking incredible. These turn out every time. The peanut butter with the chocolate chips and m&m’s is like an explosion of flavors. I can also make these festive during holidays with seasonal m&ms. Thank you!!
Thank you, Shelly! I’m so glad you’re enjoying the cookie recipes!
Perfectly chewy inside and crunchy edges. Such a delicious and easy recipe!
I accidentally doubled the white sugar (was reading the PB line), and I threw in chopped walnuts that needed to be used up… when they came out of the oven, I really didn’t think they were going to firm up and hold their shape, but they did! After the first set, I formed them into patties with my hands (because – again – I thought they weren’t going to set, hahaha) which made me feel better, but all of them came out perfect despite my errors! And delicious! Thanks so much!
These are a hit, thanks! Made with mini chocolate chips and valentine m&ms and the whole family loves them! Great texture too, a perfect mix of the oats and flour.
My cookies didn’t flatten out at all and were just like how they were when I scooped them??♀️ Other than that they tasted great and the recipe was super easy!
Thanks for the recipe! I made a double batch of these and since the bulk was going to friends with a peanut allergy, I used tahini. They turned out perfectly and for those interested, you don’t taste the peanut butter, nut butter, tahini, etc. in the cookies. It’s all about that crunchy texture from the M&Ms and the perfect soft chewiness from the oatmeal cookie. Definitely a recipe I’d make again!
I have over 1500 tested cookie recipes in my collection and this is one of the best. The cookies are crispy around the edges and chewy in the centre. They’re a nice thickness and the flavours are well balanced. I doubled the vanilla but followed the recipe otherwise. I used the weight measures and my cookies look like the ones pictured, but bigger. My yield was 17, not 32. I let the dough rest at cool room temperature for about 2 hours before baking the cookies. Because they were bigger, the cookies took 13 minutes to bake. After testing so many recipes over the years it’s hard to find one that stands out, but this one definitely does.
Wanted a monster cookie that was soft and chewy – not crispy – and a good balance of peanut butter and oats. This recipe is it! Even my anti-pb husband likes these! I get about 20 50gram cookies in a batch. These are going in my
Christmas treat box this year! Thanks for a 5 ⭐️ recipe
Made these today! Instant hit with my family. Will be adding to our favorite tried and true. They are so good! Thank you.