Monster Cookies
These are easily the BEST Monster Cookies! They’re thick and soft, loaded with oats and peanut butter, and filled with chocolate candies and chocolate chips. This recipe also includes a secret ingredient to help enhance the flavor and texture, making it unlike any other monster cookie.

What makes this the BEST Monster Cookie recipe?
With so many Monster Cookie recipes out there, why pick this one? For starters:
- The dough does not need to be refrigerated. Just mix and bake!
- It makes thick and huge (monstrous) cookies that live up to the name.
- The texture is perfection – a soft and gooey inside with a chewy outside.
- It calls for a secret ingredient never used before in a monster cookie that gives these cookies a super rich flavor and texture.
- These Monster Cookies do not fall apart!
I know I’m biased here, but seriously these are SO GOOD! They have the perfect amount of oats and peanut butter to give it that classic monster cookie flavor, but turned up just a bit. After trying these, it’ll be your new go-to recipe.


How to make the peanut butter oatmeal cookie dough
This recipe is made just like any other cookie dough, but I’m including a few extra tips to make sure you get it just right!
For starters, there’s no need to mix all the dry ingredients separate. This is a one-bowl recipe that’s super quick and easy!
In your mixing bowl, mix together the butter, peanut butter, and sugar. This can be done with a stand mixer with the paddle attachment or an electric hand mixer.
Two things here: make sure to use classic creamy peanut butter like Jif or Skippy…one that you don’t have to mix. If you use a natural peanut butter, the cookies will spread too much and the texture will be completely different.
Second, really whip the three ingredients together for a good minute until they’re light and fluffy. This helps break down and dissolve the sugar granules so you’re left with a smooth dough. If you don’t mix it enough, the cookies will turn out with a hard crust and cracked surface.
Now comes the fun part… the secret ingredient! Once properly whipped, scrape down the bowl and add vanilla, one egg, and MOLASSES! Give it a good mix until smooth and combined.
Then mix in the baking soda, salt, and oats. Mixing these in before the flour will ensure they’re evenly distributed throughout the dough. Last, mix in the flour and then fold in the mix-ins by hand to prevent over mixing.

Can you taste the molasses?
This is the secret to getting really rich and chewy monster cookies. The entire recipe only needs 2 teaspoons, so you can’t actually taste it. Don’t worry, they won’t resemble gingerbread cookies one bit. The molasses is only there to help enhance the flavors of this cookie.
It also boosts the texture to create extra softness and chewiness. Brown sugar is a combination of regular sugar and molasses, so adding a little extra molasses helps boost the effects of the brown sugar.
I’ve used this exact technique with my halloween candy cookie bars and they turned out so delicious!

Monster cookie mix-ins
A classic monster cookie includes M&M’s and chocolate chips. For my recipe, I included just these two but you can mix in whatever you want!
In the photos here, I used naturally colored candy coated chocolates that you can get at Trader Joe’s or in the bulk food section of your local health food grocer. I love the unique colors it adds to these cookies.
I also used semisweet chocolate chips because they pair really well with the peanut buttery richness of the cookies.
Other mix ins include nuts, butterscotch chips, dark chocolate chips or chunks, white chocolate chips, pretzels, toffee, or anything else you have on hand! Just as long as it all equals to 2 cups.

Monster Cookies FAQs
Yes! To freeze the dough, scoop the dough out onto a small tray or baking sheet. You can line the dough up side-by-side in order to squeeze it all onto the tray.
At this point, you can either pop the dough in the fridge for a couple hours to firm up, then toss the dough balls into a freezer bag. Or you can keep them on the tray and wrap with a couple layers of plastic wrap and then foil.
The dough will keep in the freezer for up to a month. To bake, allow the dough to thaw for about an hour before baking. Then bake as instructed.
If you only have old fashioned oats on hand, you can use those instead. Just know that the cookies will have a more chewy and bulky texture. Another option is to take your old fashioned oats and place them in a food processor. Give it a couple pulses to break up into smaller pieces.
Yes! Just substitute the all-purpose flour with a 1-to-1 gluten-free baking flour. I like Bob’s Red Mill (the blue bag) or King Arthur measure for measure. Also use certified gluten-free oats.
Substitute the egg with a flax egg! One flax egg = 1 tbsp ground flaxseed mixed with 2 1/2 tbsp water. Let it sit and gel for 5 minutes before use.
Yes, just substitute a plant-based butter. You can also use the flax egg (in previous question) to make these cookies vegan! Just make sure to use dairy-free mix-ins as well.

For more fun cookie recipes, check out my:
- Soft and Crispy Salted Caramel Chocolate Chip Cookies
- Easy Chewy Nutella Stuffed Chocolate Chip Cookies
- Thick, Soft and Chewy Sugar Cookies
- Chocolate Graham Cracker Cookies Recipe
- Dark Chocolate Chunk and Pistachio Cookies with Flaky Sea Salt
- Strawberry Cheesecake Cookies
- Brown Butter Miso Chocolate Chip Cookies
Make sure to tag me @butternutbakery on Instagram and leave a review below if you make these Monster Cookies. To pin this recipe and save it for later, you can use the button on the recipe card, the buttons above or below this post, or on any of the photos above. Happy baking!
Watch how to make these monster cookies:
Monster Cookies
- Total Time: 35 minutes
- Yield: 15 large cookies
Description
These monster cookies definitely live up to the name! They’re thick, soft, and loaded with M&M’s and chocolate chips. This recipe even includes a secret ingredient to enhance the flavor and texture.ย
Ingredients
Monster Cookies
- 1/2 cup (112g) unsalted butter, room temp (use European-style for the best flavor!)
- 1/2 cup (125g) creamy peanut butter, like Jif or Skippy
- 3/4 cup (150g) light brown sugar, packed
- 1/4 cup (50g) granulated sugar
- 1 tsp vanilla extract
- 2 tsp molasses (for texture, not taste!)
- 1 large eggย
- 1 tsp baking soda
- 1/2 tsp kosher salt
- 1 1/4 cup (125g) quick oats (use certified gluten-free if needed)
- 1 cup (130g) all-purpose flour or 1-to-1 gluten-free baking flour, spooned and leveled
- 1 cup (185g) M&M’sย
- 1 cup (185g) semisweet chocolate chips
- Flaky sea salt, for topping (optional)
Instructions
Monster Cookies
- Preheat the oven to 350F and line a large baking sheet with parchment paper.
- In a large mixing bowl with a hand or stand mixer with the paddle attachment, mix together the butter, peanut butter, and sugars on medium-high speed for a minute until light and fluffy. Scrape down the bowl.
- Mix in the vanilla, molasses, and egg until smooth and creamy. Scrape down the bowl and mix in the baking soda, salt and oats until evenly combined.
- Toss in the flour and mix until the flour is about halfway incorporated. Remove from the mixer and fold in the M&M’s and chocolate chips using a rubber spatula.
- Using a large cookie scoop (2oz) scoop 5-6 cookies onto the baking sheet (press on a couple extra candies and chips if desired). Bake for 13-15 minutes or until lightly golden around the edges with a slightly underdone center.
- Immediately top with a sprinkle of sea salt, if using, and let the cookies rest on the baking sheet for a minute before transferring to a cooling rack.
- They’re the best when they’re still slightly warm so enjoy! Otherwise, cool completely and store in a container at room temperature. They’ll remain tasty for about 5 days.ย
Notes
MIX-INS – Feel free to have fun here! You can use mini or regular M&M’s, dark chocolate chips, peanut butter chips, butterscotch chips, mini peanut butter cups, or whatever else sounds good. Just as long as it all equals 2 cups.ย
SIZE – Since they’re MONSTER cookies, we’re making extra large cookies with a 2 ounce scoop. If you’d like a more regular-sized cookie, you can scoop to your size preference and reduce the bake time. I suggest starting with 10-12 minutes.ย
- Prep Time: 20 minutes
- Cook Time: 15 minutes
- Category: Cookies
- Method: Baked
- Cuisine: American
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Meet Jenna
I’m the creator, baker, and photographer behind Butternut Bakery. Here I share desserts for every diet because I believe everyone should have a chance to indulge!





What a great recipe! I made these last weekend and they turned out beautifully. I appreciate the weight of each cookie ball listed in the instructions. It makes it so much easier to figure out how long they needed to be baked.
These cookies are so good. I put half peanut butter chips and half chocolate. I also didnโt have molasses so I used corn syrup. My husband who doesnโt like oats loves them!
Love the combination of choc chips + peanut butter + oats! Hands down my favorite cookie recipe.
Any goid substitute for the peanut butter?
Delicious. I actually made these for my kids intentionally because I’m not a fan of peanut butter… however, these are balanced so well that even I enjoyed them! Subbed out half the butter for yogurt, worked well.
These were delicious! My husband, who doesn’t like oats in his cookies, LOVED these!! Thanks for the great recipe!
Mine smell good but they fell many fell apart/crumbled in the oven. They didn’t spread like the ones in your photos. I have no idea where I went wrong! ๐
These were great! Definitely pull them out at the 15/16 minute mark even if you think they aren’t quite done… they shift to overcooked quickly! We just cooked what we could eat as they came out of the oven and froze the rest (and have already defrosted and cooked some of these) — super easy! In these days of quarantine we didn’t have molasses but maple syrup seemed to work perfectly as an on-hand alternative. YUM.
Baking these now! Mine are a little smaller and look more puffy, but delicious and super easy to bake!
Thank you!
I baked these this afternoon as my reward for cleaning up the basement from a previous day of purging. What a great reward to bake and eat. I could smell the molasses while baking but couldn’t taste it. To be sure, I ate two. I used a smaller scoop to make more cookies so I’m not feeling guilty!. And, I doubled the recipe because if I’m gonna bake, I’m gonna bake. Plus, I have a double wall oven so that makes it easy. Thanks Jenna!!!