September 15, 2023

Chocolate Monster Cookies

Monster cookies made double chocolate! Packed with rolled oats, peanut butter, cocoa and loaded with m&ms and chopped up peanut butter cups.

Yield: 10 large cookies
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Umm, yes I do already have a chocolate monster cookie recipe on the site. It’s a good one if you’re into oat flour, like a softer brownie-like cookie and won’t miss the crisp of a baked oat and it’s also gluten-free!

But, this recipe is more of a chocolate version of a classic monster cookie. They’re big cookies with big personalities: you get the chocolate and peanut butter flavor from the cookie itself which is crispy on the edges and soft/chewy in the middle, and they’re absolutely stuffed with all the yummy things: rolled oats, sliced up peanut butter cups and mini chocolate candies. 


Recipe Ingredients 

Butter: Unsalted or salted – if you are using salted I might omit the salt in the dough because coupled with the peanut butter you’re risking it being overly salty. You can add just a pinch if you know you like a well salted cookie. 


Sugar: Brown and granulated. Brown can be dark or light. Granulated should be fine or it won’t mix as well into the dough. 


Egg: Just one large. I haven’t tested these with a flax egg substitute but if I do I’ll update the recipe here! 


Cocoa: Dutch process. Some accessible brands I like: Hershey’s special dark, ghiradelli’s dutch cocoa and Guittard’s rogue. Don’t use a natural cocoa, it’s more acidic and will affect the balance of the cookie. 


Flour: All purpose. I use KAF all purpose flour. If you are looking for a gluten free option, try these oat flour monster cookies. 


Peanut butter: Smooth or chunky. I prefer a conventional brand that doesn’t need to be stirred. 


Oats: Old fashioned rolled oats, not steel cut and not quick cooking. Steel cut are just too thick and take awhile to cook, quick cooking oats can absorb some of the moisture in the dough and will dry it out. 


How to make chocolate monster cookies 


Toast the oats: this isn’t a super necessary step but I like doing it because it crisps up the oats and enhances the flavor. Set the oats in a frying pan over medium low heat and cook, stirring as it heats, until fragrant. Set aside to cool. 

Start by partially melting the butter: set cold butter in a heatproof bowl, then heat it in the microwave for about 60-90 minutes, until half of it is melted and the other half is soft enough to whisk so you have a creamy, melty butter. 

Add the sugars: both the brown sugar and the granulated. Now is a good time to add the salt and vanilla as well. Whisk vigorously, we want to aerate the dough a bit and get the sugars to start dissolving (but we aren’t quite creaming it). 

Crack in the egg: Once the egg goes in, whisk very, very well (vigorously I like to say!) until the mix is a few shades lighter than when you started. Having the added moisture from the egg will allow the sugar to dissolve more, the sugar will aerate the egg and the butter will emulsify. 

(If you wanted, you can use a hand mixer for the dough but with melted butter cookie doughs I find I can do it with a whisk.)

Scoop in the peanut butter: If you are using a scale, scoop the peanut butter directly into the bowl. If you are using measuring cups, use a silicone rubber spatula to make sure you can scrape up all the peanut butter. Whisk it in until combined. 

Measure the flour: Also if you have a scale, measure directly in. If you’re using cups fluff the flour with a spoon and then use another measuring cup to shake the flour into the measuring cup, then level it. This way you avoid packing the cup and using too much flour (which can make the cookies stiff, dry and not spread well). 


Sift in the flour and cocoa:  My cocoa has been quite lumpy lately so I sift it. If yours looks quite fine and powdery you can add it directly in. Switch to a rubber spatula to mix the dough but don’t overdo it. It’s ok if you still see streaks of flour or cocoa, they’ll get blended in in the next step. 

Fold in the oats, the candies and the chocolate bits:  If you’re using a chocolate bar or regular sized peanut butter cups, chop them up before they go into the dough. 

Add all the candies and oats at once and mix with the spatula until well blended. Cover the dough with a tea towel and set the dough aside while you prep. 

Preheat the oven and prep the pans: Grease two cookie sheets (I use either an oil spray or I’ll rub the residue from the butter wrapper on the pan) and line them with parchment paper. 


Always bake cookies on parchment; without it the cookies come in too close contact to the heat of the pan and will cook and brown quicker than they should. 


Scoop the cookie dough: I like to make these big so two tablespoons of dough per cookie. Use a cookie scoop for even distribution (here’s mine). 


Make the toppings: I’ll add some more oats (you won’t need to toast these) and some mini m&ms to one bowl and some chopped peanut butter cups to another. 

Top the dough scoops: you can dip the cookie dough into the bowl with the oats and candies and they’ll adhere nicely. For the peanut butter cup bits, press them in yourself afterwards. 

Bake: These cookies spread so leave about a 1.5-2 inch diameter of space around them to ensure they don’t touch. Bake one tray at a time on the middle rack for about 12 minutes. 


Add-ins for double chocolate monster cookies 

The classics for a monster cookie: chocolate chips and chocolate candies. But I think the classic is a missed opportunity for peanut butter cups! 

My personal favorites: chopped up dark chocolate peanut butter cups (trader joes sells the ones you see in the photos, but Reeses also makes a dark chocolate thin that would work well here) and mini m&ms. 

You can also use chocolate chips, mini, regular sized or large or chop up a chocolate bar. Regular sized chocolate candies work too! 

Keep extra of these on hand for the topping. 

Want a thicker cookie?

As you know, I bake my recipes several times until I get them exactly how I want but in the trials I will note things I liked about early tests (even if they weren’t the goal). I had a batch of these that I made quite thick I really, really liked but ultimately went with a cookie that was thinner with some more crisp.

However, if you wanted to you can make that thicker version: Up the brown sugar to 200g or 1 cup and omit the granulated sugar. Then chill the dough for an hour in the fridge, covered with cling wrap. The cookies won’t spread much so flatten them a bit with your palm so they aren’t domed.

Freezing the monster cookie dough 

If you want to bake some cookies and save the rest for a later date, or if you’d like to just have the dough ready to bake at any time: make the dough and scoop and add the toppings (you can’t add toppings to frozen dough because they’ll be too solid to press anything in). Set the dough balls on a parchment lined plate or baking sheet and flash freeze for 10-15 minutes. 

Once they’re solid, you can transfer them to a gallon ziplock bag or an airtight container. If you’re baking from frozen, add 2-3 minutes to the overall bake time. 

Double Chocolate Monster Cookies

Monster cookies made double chocolate! Packed with rolled oats, peanut butter, cocoa and loaded with m&ms and chopped up peanut butter cups.
Prep Time: 15 minutes
Cook Time: 12 minutes
Yields: 10 large cookies


  • 113g or ½ cup unsalted butter cold is fine (if using salted butter halve the amount of salt below)
  • 150g or ¾ cup brown sugar light or dark
  • 50g or ¼ cup granulated sugar
  • 1 large egg
  • 1 tsp baking soda
  • 55g or ¼ cup peanut butter chunky or creamy - use a conventional brand that doesn’t need to be stirred
  • 35 g or ⅓ cup dutch process cocoa
  • 95 g or ¾ cup all purpose flour
  • 130 gor 1 cup old fashioned rolled oats plus more for topping
  • ½ tsp fine sea salt
  • 1 tsp pure vanilla extract
  • ½ cup chopped peanut butter cups or chocolate chips plus more for topping
  • ½ cup chocolate covered candies plus more for topping


  • Toast the rolled oats in a frying pan and heat until fragrant, stirring as needed, about 2-5 minutes. Set aside to cool.
  • In a heatproof bowl, partially melt the butter (it should be half melted, half soft so that it’s stirrable).
  • Add the sugar and whisk, very well until the mix starts to look cohesive and shiny.
  • Add the baking soda, salt and vanilla and whisk well.
  • Add the egg and whisk until the mixture is light and fluffy. Whisk in the peanut butter.
  • Sift in the cocoa if it’s lumpy, add the flour and the rolled oats and stir to combine.
  • Fold in half cup of the peanut butter cups and half a cup of the candies.
  • Preheat the oven to 350 F. Line two greased cookie sheets with parchment paper.
  • Scoop the dough to about 2 tablespoons per cookie and set on the prepared pans. Arrange them so they have about a 1” diameter around them (I do about 5 cookies per pan).
  • If desired, in a separate bowl, make a topping mix with additional oats (they don’t need to be toasted), candies and chocolate.
  • Once you’ve scooped the cookies, dip them into the mix and use your hands to press bits of chocolate and candy into the top (the oats will stick on their own).
  • These cookies will spread so leave space around them. Bake the cookies for about 10-12 minutes.
  • Store in an airtight container.

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Recipe Reviews

  1. My son would love these! I have a question, what is the point of greasing the cookie sheet if you also use parchment paper? I bake my cookies on parchment as well, but haven’t greased the sheet before. Is it specific to this recipe?