Monster Cookies

Thick, chewy Monster Cookies that are absolutely loaded with fun add-ins. Today’s cookies are packed with oats, peanut butter, chocolate and butterscotch chips, and M&Ms!

This cookie recipe is something of a cross between my peanut butter cookies, oatmeal cookies, and M&M cookies. Simple but hearty cookies that can be customized to your preference. This Monster Cookie recipe includes a step-by-step video at the end of the post! 

Stack of monster cookies

Monster Cookies

I’m not sure who named Monster Cookies or what they were thinking when they did so, but in so many ways this name is fitting.

Monster cookies, because they are something of a monstrosity to the cookie world. A jumble of peanut butter, oatmeal, and chocolate chip cookies rolled into one Frankenstein’s monster of a cookie.

Monster cookies, and because they turn you into a legit cookie monster (I ate half the tray of cookies before they could even finish cooling 🙈).

Monster cookies, because these cookie cravings turn you into something worth than just a cookie monster if you can’t get your hands on a second, third, fourth, etc. fast enough. Seriously, don’t stand between me and a tray of warm cookies. It’s for your own good ♥︎.

Whatever the reason, these cookies aremega addicting. The cookie base is soft but hearty (thanks to a ton of add-ins), a blend of chewy oats, melty chocolate, crisp candyshell, distinct peanut butter flavor… These cookies have it all.

Monster Cookie Dough

Let’s Talk Add-Ins

OK, so let’s talk about the add-ins. While you won’t want to change up the peanut butter or the oats (otherwise you risk altering the base and the outcome of the cookie), we do have plenty of wiggle room with our other additions.

I added M&M candies, semisweet chocolate chips, and butterscotch chips to my Monster Cookies. You can swap out the candy pieces for a different chopped up candy (I’ve used chopped up Rolos before, just keep the caramel inside the cookie dough as much as possible when you scoop it!), or substitute different chocolate chips. I liked the blend of half semisweet and half butterscotch chips, but peanut butter chips or caramel chips would also be great additions!

Oh, toffee bits would also be great! Guess I have an excuse to make another batch now.

Monster Cookies cooling on rack

Monster Cookies are perfect for the cookie monster in all of us.


Be sure to check out the Monster Cookie video at the bottom of the recipe! If you enjoy watching, make sure to subscribe to my YouTube channel where I’ve already uploaded over 100 recipe videos that you can watch for free!

Monster Cookies

Monster Cookies

Thick, soft, and chewy Monster Cookies that are absolutely loaded with add-ins. Today's cookies are packed with oats, peanut butter, chocolate and butterscotch chips and M&Ms. Be sure to check out the VIDEO at the bottom of the recipe!
5 from 6 votes
Print Pin Rate
Course: Cookies, Dessert
Cuisine: American
Keyword: best cookies, cookies, monster cookies
Prep Time: 15 minutes
Cook Time: 11 minutes
Chilling Time: 30 minutes
Total Time: 26 minutes
Servings: 18 cookies
Calories: 255kcal
Author: Sam


  • 10 Tablespoons unsalted butter softened to room temperature 141g
  • 2/3 cup light or dark brown sugar tightly packed, 135g
  • 1/4 cup sugar 50g
  • 1/2 cup creamy peanut butter* 140g
  • 1 large egg
  • 1 teaspoon vanilla extract
  • 1 cup all-purpose flour 125g
  • 1 teaspoon cornstarch
  • 3/4 teaspoon baking soda
  • 3/4 teaspoon salt
  • 1 cup quick oats 115g
  • 1/3 cup butterscotch chips 60g
  • 1/3 cup semisweet chips 60g
  • 1/2 cups M&M candies 100g


  • Combine butter, sugars, and peanut butter in the bowl of a stand mixer (or in a large bowl and use an electric mixer) and beat until creamy and well-combined.
  • Add eggs and vanilla extract and stir well.
  • In a separate bowl, whisk together flour, cornstarch, baking soda, and salt.
  • Add your flour mixture to your wet ingredients and stir (with mixer on low speed so that you don't send flour flying everywhere!) until flour is completely incorporated into the batter. Be sure to scrape the sides and bottom of the bowl so that ingredients are well-combined.
  • Add oats, chocolate and butterscotch chips, and M&Ms and stir well.
  • Cover cookie dough with plastic wrap and transfer to the refrigerator. Allow dough to chill for at least 30 minutes (this dough may be chilled longer or even overnight if needed).
  • 15 minutes before dough is finished chilling, preheat your oven to 350F (175C) and line cookie sheet with parchment paper.
  • Once dough has chilled, remove from the refrigerator and roll into 1 1/2 Tablespoon-sized balls and place on prepared cookie sheet, spacing cookie dough at least 2" apart.
  • Bake on 350F (175C) for 11-12 minutes or until edges are beginning to turn light golden brown. Allow cookies to cool completely on baking sheet before enjoying.



*I don't recommend using natural peanut butter


Serving: 1cookie | Calories: 255kcal
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