This Monster Cookie Recipe is one of our go to cookies when we want something easy, filling, and loaded with all the good stuff. With peanut butter, oats, chocolate chips, and M&Ms, these cookies are packed with flavor, texture and deliciousness.

Weโ€™ve made these cookies for years, and theyโ€™re always a hit with both kids and adults. Theyโ€™re soft, chewy, and full of chocolate in every bite. Plus, theyโ€™re simple to make and great for sharing. If you love easy desserts, check out our full collection of cookie recipes.

If you loved this, try Chocolate Chip Cookies, Peanut Butter Cookies, Oatmeal Cookies, or M&M Cookies. These are all favorites we keep in rotation!

Why you’ll love it + Why it works:

  • Loaded with Mix-Ins. Chocolate chips and M&Ms make every bite fun and flavorful.
  • Soft and Chewy. These cookies stay soft with the perfect texture.
  • Oats for Texture. Oats plus peanut butter create a soft, thick cookie that holds mix ins well.
  • Balanced Sweetness. Using two types of chocolate chips gives a deeper flavor and lots of melty bites.
Ingredients for monster cookie recipe on a kitchen counter.
  • Peanut Butter (1ยฝ cups, creamy or chunky): Acts as the base and helps hold the cookies together while adding rich flavor.
  • Brown Sugar (1 cup, packed): Adds moisture and helps create a soft, chewy texture.
  • Sugar (1 cup): Sweetens the cookies and helps with structure.
  • Unsalted Butter (ยฝ cup, room temperature): Adds richness and helps create a tender texture.
  • Eggs (2 large): Binds everything together and adds structure.
  • Vanilla Extract (1 tablespoon): Enhances all the flavors in the cookies.
  • Quick Cooking Oats (4ยฝ cups): Adds chewiness and gives the cookies their hearty texture.
  • Baking Soda (2 teaspoons): Helps the cookies rise and spread properly.
  • Milk Chocolate Chips (1 cup): Adds melty chocolate throughout the cookies.
  • M&Ms (1 cup): Adds color, crunch, and extra sweetness.

Preheat oven to 350ยฐF. Prepare a cookie sheet by lining it with parchment paper or using cooking spray.

In the bowl of a stand mixer, combine sugars and butter and beat until fluffy. Add eggs and beat until fluffy, followed by the peanut butter, vanilla and baking soda. Add oats and flour and mix to combine.

Stir in M&M and chocolate chips and mix until just combined.

Use a large cookie scoop to place dough on the prepared baking sheet. (To make them picture perfect add a few chocolate chips and M&Ms to the top of the scoops. I love this trick!)

Bake for 10-12 minutes, and let cool on the baking sheet for 5 minutes before moving to a wire rack to finish cooling.

  • Cookie Scoops: Bake for 10 to 12 minutes.
  • Ice Cream Scoops: Bake for 18-20 minutes. Be sure you do not over-bake!!
Several monster cookies on a cooling rack.

Kristyn’s Recipe Tips

  • Donโ€™t Overbake: Cookies should look slightly underdone for the best chewy texture.
  • Use a Scoop: Keeps cookies uniform and evenly baked. Use a large cookie scoop for even baking and that classic thick monster cookie look. For cleaner scooping, chill the dough for 15 to 20 minutes if it feels sticky.
  • Add Extra Toppings on Top: Press a few extra M&Ms and chocolate chips on top before baking for a bakery style finish.
  • Let Them Rest: Let the cookies cool on the baking sheet for 5 minutes; it helps them set so they do not fall apart.
  • Peanut butter holds these cookies together, so use regular brands like Jif or Skippy. Natural or almond butter may make them crumbly, but crunchy works for added texture.
  • Oats: I used quick oats because I like the texture and structure that it creates within the cookie. You can use regular oats if that is what you have on hand, but do not use steel-cut oats or instant oats.
Monster cookie recipe on a cooling rack.
5 from 37 votes

Monster Cookie

Monster Cookies are thick and chewy oatmeal peanut butter cookies loaded with chocolate chips and M&Ms, a family favorite cookie recipe.
Servings: 36
Prep: 15 minutes
Cook: 10 minutes
Total: 25 minutes

Video

Ingredients 

  • 1ยฝ cups creamy peanut butter or chunky
  • 1 cup brown sugar packed
  • 1 cup sugar
  • ยฝ cup unsalted butter room temperature
  • 2 large eggs
  • 1 tablespoon vanilla extract
  • 4ยฝ cups quick cooking oats
  • 2 teaspoons baking soda
  • 1 cup milk chocolate chips
  • 1 cup plain M&Ms

Instructions 

  • Prepare a cookie sheet by lining it with parchment paper or using cooking spray. Preheat the Oven to 350ยฐF.
  • Use an electric mixer to combine peanut butter, sugars, and butter. Mix well then add the eggs and vanilla. Next, mix in the quick oats and baking soda. Finally, stir in the chocolate chips and M&M's.
  • Use a cookie or ice cream scoop to drop the dough onto the baking pan. (To make them picture perfect add a few chocolate chips and M&Ms to the top of the scoops.)
  • Cookie scoops: Bake for 10 to 12 minutes. Ice Cream Scoops: bake for 18-20 minutes. Be sure you do not overbake!!
  • Allow the cookies to cool for a few minutes before transferring them to a wire rack to finish cooling off.
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Notes

Recipe Tips.
  • Add Extra Toppings on Top: Press a few extra M&Ms and chocolate chips on top before baking for a bakery style finish.
  • Peanut butter holds these cookies together, so use regular brands like Jif or Skippy. Natural or almond butter may make them crumbly, but crunchy works for added texture.
  • Oats: I used quick oats because I like the texture and structure that it creates within the cookie. You can use regular oats if that is what you have on hand, but do not use steel-cut oats or instant oats.
Store. Keep cookies in an airtight container at room temperature for up to 4 days. Freeze cooled cookies in a freezer bag for up to 2 months. Thaw: Thaw at room temperature, or warm briefly for a fresh-baked feel.ย 
Freeze the cookie dough. Scoop dough balls onto a baking sheet, freeze until firm, then store in a freezer bag for up to 2 months. Bake from frozen, adding 1 to 2 minutes.ย 
Gluten free. These cookies are made without using flour. However, you need to check the other ingredients, like the oats, to be sure they do not contain hidden gluten.

Nutrition

Calories: 228kcal, Carbohydrates: 28g, Protein: 5g, Fat: 12g, Saturated Fat: 5g, Cholesterol: 22mg, Sodium: 125mg, Potassium: 119mg, Fiber: 2g, Sugar: 19g, Vitamin A: 123IU, Vitamin C: 1mg, Calcium: 30mg, Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Recipe FAQ

How to store?

Keep cookies in an airtight container at room temperature for up to 4 days.
Freeze cooled cookies in a freezer bag for up to 2 months.
Thaw: Thaw at room temperature, or warm briefly for a fresh-baked feel.

How to freeze the cookie dough?

Scoop dough balls onto a baking sheet, freeze until firm, then store in a freezer bag for up to 2 months. Bake from frozen, adding 1 to 2 minutes.

Are oatmeal monster cookies gluten-free?

These cookies are made without using flour. However, you need to check the other ingredients, like the oats, to be sure they do not contain hidden gluten.

This recipe was first shared April, 2020.

About Kristyn

Kristyn Merkley is a published cookbook author, wife, mom of six, and major food enthusiast! For the past 15 years, she has been sharing foolproof, family-friendly recipesโ€”each one tested in her kitchenโ€”that anyone can master. As a seasoned recipe creator, she loves making cooking simple, stress-free, and totally doable for everyone!

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5 from 37 votes (23 ratings without comment)

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24 Comments

  1. Sheila L Osborne says:

    I’m wondering if I could add Kraft caramel bits to these without ruining the recipe. Your opinion?

    1. Lil' Luna Team says:

      You should be able to add them to the cookie dough. However, keep in mind that any pieces that poke out of the dough may melt out a bit.

  2. Carla Bradshaw says:

    Can the dough be frozen?
    Thank you!

  3. Julie says:

    5 stars
    These are THE BEST cookies ever! Shared some with host at our campground and he said they were the best cookies he’s ever had! Totally agree! (I used semisweet chocolate chips rather than milk chocolate.)

  4. Susan Elson says:

    I made these sugar free with stevia sugar and 2 kinds of sugar free chocolate chips! What can be better than gluten free and sugar free ๐Ÿช

    1. Lil'Luna Team says:

      I’m glad to hear they turned out well with no sugar! Thanks for sharing. Glad you enjoyed the cookies!

  5. Mary says:

    5 stars
    These are amazing! I’ve made a couple different monster cookie recipes and this is hands down the best!

    1. Lil'Luna Team says:

      Oh that makes me so happy to hear!! Glad you love the cookie recipe!

  6. Marty says:

    5 stars
    Monster cookies are a staple whenever grandkids visit! They love them (and so do we)!I use holiday M&Ms for the seasons!

  7. Jen fischer says:

    5 stars
    Sooo yummy!

    1. Jenn says:

      Can I reduce the amount of sugar? If so how much is safe without changing the batter/texture etc

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