Baker Bettie

Soft and Chewy Monster Cookies

I’m showing you how to make the best monster cookies! They are soft and chewy and filled with chocolate chips, M&M’s, salty peanut butter, and oats! They hit every texture and flavor note you want in a cookie! 

Monster Cookies Overview

This is my absolute favorite monster cookie recipe. They turn out incredibly soft and chewy and with lots of texture from the addition of the oats. I find these to be an elevated version of the chocolate chip cookie. 

What are Monster Cookies? 

Monster cookies are a a peanut butter chocolate chip cookies with M&M’s and oats. The cookie base is kind of a hybrid of a traditional chocolate chip cookie and a peanut butter cookie

Monster cookies are typically made with regular M&M’s but can also be made with mini M&M’s or any other variety. I also like to use only dark brown sugar and no white sugar in the cookies to give them the most chew. 

How to Make Monster Cookies

Monster cookies are made with the same mixing method as traditional chocolate chip cookies- the creaming method. This means it is important that your butter and egg are at room temperature before starting the process. But as a bonus, this cookie dough requires no chilling! 

Step 1: Cream together the Fat & Sugar

Butter, peanut butter, and brown sugar after being creamed for monster cookie dough

You want to start by creaming the butter and peanut butter together with the brown sugar. I like to use dark brown sugar in my monster cookies because it will give the most chew and most flavor. But you could also use light brown sugar. 

Step 2: Add the Egg & Vanilla

Next you will mix in the vanilla extract and egg. I think a really good quality vanilla extract can really elevate a cookie to the next level. I love using Nielsen-Massey pure vanilla extract in my cookies. 

Step 3: Incorporate the Dry Ingredients

Dry ingredients for monster cookies in a bowl before being mixed

Whisk together all of the dry ingredients in a separate bowl. You want to make sure you are using quick cooking oats in these cookies as it will give the best texture and structure to the cookies. If you only have rolled oats available, pulse them in a food processor a few times to make them a bit smaller. 

Step 4: Fold in the Mix-Ins

Monster cookie dough in a bowl with a spatula in it.

And next we will fold in the chocolate chips and M&M’s. You can use any variety of M&M’s you like, but I usually just stick with the standard ones. 

I also prefer to use semi-sweet or bittersweet chocolate chips to contrast the milk chocolate in the M&M’s. The two sweetness levels really makes the cookies have a more complex flavor profile. 

Step 5: Scoop, Top, & Bake

Scoop large mounds of cookies onto your baking sheet. I use a large cookie scoop for this, but you could also just use a spoon. You want them to be about 3 TBSP in size for the best texture after baked. 

Top each cookies with a few more chocolate chips and M&M’s so that they look really pretty once they are pulled out of the oven. You could also sprinkles with a little flaky salt if you like! 

How do I keep my Cookies from Spreading? 

A higher baking temperature will allow cookies to set before the butter melts and they spread out completely. These are baked at 375 F which is higher than most cookie recipes. 

If your cookies are spreading too much it is possible that your oven isn’t getting quite up to the temperature you set it at and you might need to set it a bit higher. 

Why are my Cookies Falling Apart? 

Cookies can sometimes fall apart if you over measured your flour. Be careful not to pack the flour down into your measuring cup at all when measuring it. 

Oatmeal cookies can also tend to fall apart sometimes. This is why I prefer adding quick oats into my monster cookies because it helps give the best texture and helps hold the cookie together better. 

Monster cookies on a baking sheet

Tips for Making the Best Monster Cookies

  • Dark brown sugar will make the chewiest and most flavorful monster cookies. 
  • Make sure you are using quick cooking oats or rolled oats that have been pulsed in a food processor. 
  • Use semi-sweet or bittersweet chocolate chips to contrast the milk chocolate in the M&M’s. 
  • Top each cookie with a few extra chocolate chips and M&M’s before baking. This will make them look really pretty when they come out of the oven. 
  • Sprinkle a little flaky salt over the top before baking to really elevate them to the next level! 
Monster Cookies

Monster Cookies

Yield: 12 Large Cookies
Prep Time: 15 minutes
Cook Time: 8 minutes
Total Time: 23 minutes

This is absolutely my favorite monster cookie recipe! They are soft and chewy and filled with chocolate chips, M&M's, salty peanut butter, and oats! They hit every texture and flavor note you want in a cookie! 


  • 1/2 stick (1/4 cup, 57 gr) unsalted butter, softened
  • 1/3 cup (85 gr) creamy peanut butter
  • 3/4 cup (170 gr) brown sugar, lightly packed (preferably dark brown sugar)
  • 1 large egg, room temperature
  • 1 tsp vanilla extract
  • 1/2 tsp baking powder
  • 1/2 tsp baking soda
  • 1/2 tsp kosher salt
  • 1 cup (120 gr) all purpose flour
  • 1/2 cup (50 gr) quick oats (*see note for using rolled oats)
  • 1/2 cup (120 gr) chocolate chips + plus more for topping
  • 1/2 cup (120 gr) M&M's + plus more for topping


  1. Preheat the oven to 375 F (190 C). Position an oven rack in the center position.
  2. In the bowl of a stand mixer fit with a paddle attachment (or large mixing bowl with a hand mixer) cream the butter, peanut butter and brown sugar together on medium/high speed until light and fluffy. This should take about 3-5 full minutes.
  3. Scrape down the sides and the bottom of the bowl. Add the egg and vanilla and continue mixing on medium speed until just incorporated.
  4. In a separate mixing bowl, whisk together the flour, baking powder, baking soda, salt, and quick oats. You want to use quick oats for the best texture of the cookies. If you only have rolled oats, pulse them in a food processor a few times until they are a bit smaller. If you do not have this option, you can use the rolled oats as is, but be aware the cookies will not spread quite as much and the texture will be a little different.
  5. Add the dry ingredients into the mixing bowl and mix until they are just incorporated. You do not want to overmix or your cookies will become tough.
  6. Take the mixing bowl off of the mixer and use a rubber spatula to fold in the chocolate chips and M&M's.
  7. Use a large cookie scoop (or a spoon) to form large dough mounds. I think these work best with about 3 TBSP worth of dough per cookie. I use a 2 oz scoop that is not filled all the way.
  8. Top each dough mound with a few more chocolate chips and M&M's to give a nice appearance after baking. You can also sprinkle a little flaky salt over the top if you like.
  9. Bake 1 cookie sheet at a time for 8-10 minutes. Pull them from the oven when the edges are set and the centers still look slightly under baked. Allow to cool on the cookie sheets. This will let them finish cooking and set the cookies.
  10. Store cooled cookies at room temperature in an airtight container for up to 1 week.


  • If you only have rolled oats on hand, pulse them a few times in a food processor until they are slightly smaller and closer to quick cooking oats. This will give the best texture for your cookies.
  • If you want to make smaller cookies, reduce the oven temperature to 350 F and check on the cookies at the 8 minute mark to see how fast they are cooking.

Recipe adapted from my Soft and Chewy Chocolate Chip Cookies

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