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Embrace your inner Cookie Monster with these M&M and chocolate chip laden Monster Cookies that are also loaded with plenty of chewy oats and creamy peanut butter! Just try your best to resist the dough so you can actually bake some of these first!

We bake a batch of cookies every week! Some of our other favorites are Andes Mint Cookies, Soft Banana Pudding Cookies and classic Snickerdoodles!

Homemade monster cookies cooling on a rack.

Monster cookies are a fun and fantastic way to get all of your favorite cookie experiences in one. They’re a combination of your favorite Peanut Butter and M&M cookies, and Oatmeal Chocolate Chip Cookies all rolled into one. With so much going on in every bite it’s a perfect blend of happiness.

What are monster cookies?

Personally, I think the best reason for calling these monster cookies is their massive size. They are monster-sized cookies for sure if you make large balls of dough!

But another theory for the name is that monster cookies are a hybrid of a few other cookies rolled up in one. Sort of like Dr. Frankenstein’s monster, these cookies pull together bits and pieces of various recipes and make one unique creation.

What are monster cookies made of?

Monster cookies are made using a combination of basic brown sugar cookie dough, chocolate chips, peanut butter, oats, and M&Ms.

Of course several other optional mix-ins can include shredded sweetened coconut, butterscotch chips, chopped peanuts, or even broken pretzel pieces for a salty/sweet combination!

Peanut butter oatmeal monster cookies on parchment paper.

How to make monster cookies

  1. Prep: Preheat your oven to 350F degrees and line two baking sheets with parchment paper. Set them aside.
  2. Cream butter and sugar: In the bowl of a stand mixer, beat together the butter, the peanut butter, and the sugars until creamy and light, about 2 minutes.
  3. Mix some more: Add in the eggs and the vanilla, and beat again. Scrape down the sides of the bowl often and mix until everything is combined.
  4. Add in dry ingredients: Mix in the oats, flour, baking soda, and salt until just combined. Don’t overmix though or you will end up with dense, tough cookies. Stir in ¾ cup of the mini M&Ms and the chocolate chips.
  1. Scoop: Use a large cookie scoop (¼ cup sized) to scoop the dough into large mounds of dough on the prepared baking sheets. You should be able to fit about 8 cookies per sheet. Remember to space them out so that the cookies can spread a bit without sticking. Press some reserved M&Ms onto the tops of the cookies.
  2. Bake: Bake in the oven for 10 minutes or just until they become set around the edges. Do NOT over bake these cookies, they will appear slightly underdone and will continue to set up as they cool.
Eight balls of monster cookies dough on a baking sheet.
  1. Garnish: Immediately press the reserved chocolate chips onto the cookies and then transfer onto a wire rack to cool completely.
Large monster cookies on a wire rack with mini M&Ms.

Who invented monster cookies?

Monster cookies were originally created in 1971 by Mr. Dick Wesley, a University of Michigan photographer. He was the father of 6 kids and constantly trying to find new ways to use up what they had on hand. His original recipe included candy coated chocolates (like M&Ms) as well as leftover jam that the kids weren’t eating fast enough.

He also blended oats to create a flour base, instead of using actual flour. As you can see, the recipe has since been modified quite a bit as time went on. Most versions these days have abandoned the jam and oat flour base in favor of a mix of oats and all-purpose flour.

Cookies with chocolate chips and mini M&M's.

Can I use old fashioned oats instead of quick oats?

Yes, you can. Using them as-is will create chewy oats because they won’t fully cook and soften during the baking process. To use them and get them into a more enjoyable texture, I recommend placing the oats in a blender or a food processor (affiliate link) and then pulsing them a few times to chop them up into smaller pieces first.

Can I freeze monster cookies?

Yes, these cookies are great for freezing. Simply let the cookies cool completely and then place them in an airtight container in the freezer for up to 6 months. Remove a cookie and let it thaw on the counter for about 30 minutes before eating so that they aren’t rock solid.

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Monster Cookies
Yield: 12-14 large cookies

Monster Cookies

Embrace your inner Cookie Monster with these M&M and chocolate chip laden Monster Cookies that are also loaded with plenty of chewy oats and creamy peanut butter! Just try your best to resist the dough so you can actually bake some of these first!

Prep Time 10 minutes
Cook Time 10 minutes
Total Time 20 minutes

Ingredients

  • 1/2 cup salted butter, softened
  • 1 cup creamy peanut butter
  • 3/4 cup granulated sugar
  • 1/4 cup light brown sugar, packed
  • 2 eggs, room temperature
  • 2 teaspoons vanilla extract
  • 1 cup all-purpose flour
  • 1 teaspoon baking soda
  • 1 teaspoon cornstarch
  • 1/2 teaspoon salt
  • 1 1/2 cups quick oats
  • 1 cup mini m&m's, divided
  • 3/4 cup semisweet chocolate chips, divided

Instructions

  1. Preheat oven to 350 degrees F. Line two baking sheets with parchment paper.
  2. In the large bowl of a stand mixer, beat the butter, peanut butter, and sugars on medium-high speed for 2 minutes until creamy and light.
  3. Add eggs and vanilla and beat again, scraping the sides and bottom of the bowl until everything is combined.
  4. Add the oats, flour, baking soda, and salt. Mix just until combined.
  5. Stir in 3/4 cup each of the mini m&m's and chocolate chips.
  6. Use a large 1/4 cup cookie scoop to scoop mounds of cookie dough onto the prepared baking sheets, about 8 cookies per sheet. Space them out so they can spread a bit without touching. Press the reserved m&m's into the tops of each cookie.
  7. Bake for 10 minutes, just until set around the edges. Do NOT overbake these cookies. They may look slightly underdone, but they will continue to set up on the pan. Immediately press a few of the reserved chocolate chips into the top of each cookie. Transfer the cookies to a wire rack to cool completely.

Notes

  • If you don't have quick oats on hand, you can use old-fashioned oats. Just pulse them in a blender or food processor a few times to chop them a bit smaller first.

Nutrition Information:

Yield:

14

Serving Size:

1

Amount Per Serving: Calories: 410Total Fat: 23gSaturated Fat: 10gTrans Fat: 0gUnsaturated Fat: 11gCholesterol: 46mgSodium: 346mgCarbohydrates: 47gFiber: 3gSugar: 30gProtein: 8g

All nutritional information is based on third party calculations and is only an estimate. Each recipe and nutritional value will vary depending on the brands you use, measuring methods and portion sizes per household.