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Halloween Monster Cookies Recipe

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Halloween Monster Cookies are festive, sweet oatmeal chocolate chip cookies that are ghoulishly delicious and so simple to make with plenty of chocolate, peanut butter, Halloween M&M’s, and fun, goofy candy eyes.

Closeup top view of Halloween Monster Cookies with candy eyes

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Crisp on the edges, and chewy in the center with gooey chocolate melted throughout, these Monster cookies are a classic favorite, especially for Halloween!

Always a hit with family and friends, these Monster Mash Cookies are not only delicious, they’re fun to make too!

Monster Cookies

It’s difficult to choose a favorite cookie. So many different flavors and textures, but these Monster Cookies always have a place at the cookie table! Most especially for Halloween, but honestly, anytime. Simply change the color of the M&M’s for any occasion.

Here’s what I love best about these Monster oatmeal chocolate chip cookies:

  • Super soft and chewy texture
  • Oatmeal, chocolate chip, and peanut butter flavors in one cookie!
  • Candy eyes! They make me smile every time.
  • No dough chilling needed!
Top view of Monster Cookies with M&Ms on a black paddle board with pumpkins in the background

Why are they called Monster Cookies?

I wish I knew! Some people say they’re called Monster Cookies because of their bumpy texture and wacky colors. Others say they’re much like Kitchen Sink cookies because they are filled with a variety of ingredients, others refer to their large size.

Whatever the reason, they are a fun, festive… and delicious homemade cookie. And those eyes! While obviously completely optional, for Halloween, they’re rather fun.

Top view of ingredients for Halloween Monster Cookies on a round wood cutting board

Halloween Monster Cookies Ingredients

The exact ingredient measurements are in the recipe card at the very bottom of this post, but here’s an overview of what’s in these monster cookies:

  • Unsalted butter softened to room temperature
  • Light brown sugar and granulated sugar
  • Large eggs
  • Peanut butter (smooth or chunky works equally well
  • Oatmeal: I like to use old fashioned rolled oats
  • All-purpose flour
  • Leavening: both baking soda and baking powder, plus salt
  • Vanilla extract for flavor
  • Halloween M&Ms
  • Chocolate chips
  • Candy eyes (optional)

How to make Monster Cookies

Again, the step-by-step instructions are in the recipe card at the bottom of this post, but here’s an overview:

  • Cream the butter and sugars until light and fluffy for the best texture. Then stir in the wet ingredients of eggs, peanut butter, and vanilla.
  • Add the dry ingredients to the wet ingredients and mix until just combined. Stir in the oats, chocolate chips and M&M’s.
  • Bake in a 350° oven for 10 to 12 minutes, or until just set. Let cool on the baking sheet before transferring to a rack to cool.

Halloween Monster Cookie Tips

  • Slightly underbake the cookies. You want the tops to look just set as they will continue to bake and harden as they cool on the baking sheet.
  • To get the Halloween M&M colors to shine, I like to add a few to the cookies as soon as they come out of the oven for an extra festive touch.
  • Add the candy eyes to the cookies just as they come out of the oven.

How to Store Monster Cookies

Store these cookies in an air-tight container at room temperature for 1 to 2 days. You can also freeze the cookie dough or baked cookies for longer storage.

To freeze cookie dough, scoop into balls and store in a freezer safe container. When ready to bake, place the frozen cookie dough balls onto a baking sheet and add 2 to 4 minutes to the baking time.

To freeze baked cookies, let them cool completely before storing in a freezer safe container for up to 3 months.

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Top closeup view of Halloween Monster Cookies with M&Ms and candy eyes
Closeup top view of Halloween Monster Cookies with candy eyes

Halloween Monster Cookies

Yield: 24 servings
Prep Time: 10 minutes
Cook Time: 10 minutes
Total Time: 20 minutes

Halloween Monster Cookies are festive, sweet oatmeal chocolate chip cookies that are ghoulishly delicious and so simple to make with plenty of chocolate, peanut butter, Halloween M&M's, and fun, goofy candy eyes.


  • 1 cup (235g) unsalted butter, softened
  • 3/4 cup (150g) packed light brown sugar
  • 1/2 cup (100g) granulated sugar
  • 2 large eggs
  • 1 cup (260g) peanut butter (smooth or chunky)
  • 2 teaspoons vanilla extract
  • 1 and 1/2 cups (188g) all-purpose flour
  • 1 teaspoon baking soda
  • 1 teaspoon baking powder
  • 1 teaspoon salt
  • 2 cups (180g) oats (Old Fashioned or Quick)
  • 1 cup (200g) Halloween M&Ms
  • 1 cup (170g) chocolate chips
  • Candy eyes (optional)


  1. Preheat the oven to 350°F. Line baking sheets with parchment paper and set aside.
  2. In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, brown sugar, and granulated sugar until light and fluffy. Beat in the eggs, one at a time, and then beat in the peanut butter and vanilla until well combined.
  3. Combine the flour, baking powder, baking soda, and salt; add to the mixer and mix until combined. With the mixer on low, add the oats until combined, then mix in the M&Ms and chocolate chips. I like to reserve some M&Ms to add to press into the cookies before they're completely baked.
  4. Scoop mounds of cookie dough onto prepared baking sheets at least 2 inches apart. Bake for 8 to 10 minutes, or until light golden brown.
  5. Remove from the oven and let sit on the baking sheet for a few minutes before transferring to a wire rack to cool. while the cookies are still warm, I like to press a few more M&Ms into the cookies and add the candy eyes too.

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