Soft-Baked Monster Cookies

Monster cookies are peanut butter cookies with oats, chocolate chips, and M&Ms. My easy monster cookie recipe yields extra soft and thick cookies and you don’t need to chill the cookie dough! 

Monster cookies with M&Ms

For as much as I love peanut butter cookies and oatmeal cookies, I’ve never published a monster cookies recipe on my blog before. To be honest, the reason I’ve never shared one is because it’s taken me almost 3 months to develop one I’m proud enough to publish. Too flat, too puffy, falling apart, rock hard, too dry, and too sweet peanut butter oatmeal cookies have all made their way in my kitchen lately. But I’ve finally found that “perfect” one and I’m so excited to show you!

Cookie dough balls on cookie sheet before baking

stack of 2 monster cookies

What Makes These Monster Cookies Different?!

My monster cookie recipe is unlike most traditional recipes. It’s more like a peanut butter cookie with oats, rather than an oatmeal cookie with peanut butter. Other aspects setting these monster cookies apart from the rest:

  1. Mega soft-baked texture
  2. Extra thick, just look at the picture!
  3. No dough chilling required

This recipe doesn’t make 5-6 dozen cookies like most monster cookie recipes requiring a hefty load of ingredients. Rather, my recipe uses a small amount of ingredients and yields 2.5 dozen medium-sized cookies. They aren’t actually “monster” in size, but feel free to roll them larger.

Peanut butter oatmeal cookies

Quick Oats are Key

Use quick oats. Why? Quick oats are more finely cut whole oats and will give the monster cookies a more uniform texture. Furthermore, quick oats will act more as a binder since the consistency is more powdery. If you don’t have quick oats, pulse your whole oats in the food processor a few times to break them down.

Helpful tip: The cookies spread just slightly while baking, so press them down with a spoon after you remove them from the oven. That’s what gives the cookies their crinkled tops.

Quick Monster Cookies: No Dough Chilling!

Like I mentioned, this is a quick cookie recipe. There is no dough chilling needed for these monster cookies! The dough is thick and sturdy enough to bake right away. However, should you bake the monster cookies with a thinner peanut butter or on a particularly humid day, chill in the refrigerator for up to 30 minutes. Cookie dough can be picky. Go by how your dough feels. If it’s too sticky, chill for 30 minutes. If not, just bake.

More no dough chilling cookie recipes. I have tons!

Monster oatmeal cookies on a blue plate

These cookies remain exceptionally soft for days… if they last that long. I also find that the peanut butter flavor is intensified after day 1, too. Just wait until your first bite!

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Monster cookies with M&Ms

Soft-Baked Monster Cookies

  • Author: Sally
  • Prep Time: 10 minutes
  • Cook Time: 20 minutes
  • Total Time: 40 minutes
  • Yield: 2.5 dozen
  • Category: Dessert
  • Method: Baking
  • Cuisine: American


These are the best monster cookies ever! They’re deliciously packed with peanut butter, oats, M&Ms, and chocolate chips. No bite is boring! The cookies are soft-baked style and extra thick. No cookie dough chilling required, so this cookie recipe is simple and quick! 


  • 1/2 cup (1 stick or 115g) salted butter, softened to room temperature*
  • 1/2 cup (100g) packed light brown sugar
  • 1/4 cup (50g) granulated sugar
  • 3/4 cup (185g) creamy peanut butter
  • 1 large egg, at room temperature*
  • 1 teaspoon pure vanilla extract
  • 1/2 teaspoon baking soda
  • 1 and 1/4 cups (156g) all-purpose flour (spoon & leveled)
  • 1/2 cup (40g) quick oats*
  • 3/4 cup (150g) M&Ms (any size or variety)
  • 1/2 cup (90g) semi-sweet chocolate chips


  1. Preheat oven to 350°F (177°C). Line baking sheet with parchment paper or silicone baking mat.
  2. In a large bowl, using a hand-held mixer or stand mixer with paddle attachment, cream the butter and sugars together on medium speed, about 3 minutes. Mix in the peanut butter, egg, and vanilla (in that order). Scrape down the sides of the bowl as needed. Slowly mix in the baking soda and flour. Do not over-mix. On low speed, beat in the quick oats, M&Ms, and chocolate chips just until incorporated. If the dough is very soft and unmanageable by hand, chill the dough for 30 minutes before rolling.
  3. Rolls balls of dough, about 2 Tablespoons of dough per ball, onto prepared baking sheet. Press a few extra M&Ms on top for looks, if preferred. Bake for 11-13 minutes– the cookies will still look a little soft, which is recommended. Slightly press down the baked cookies with the back of a spoon, since the cookies only slightly spread in the oven. Allow cookies to cool on baking sheet for 10 minutes before transferring to a wire rack. Cookies will firm up as they cool.
  4. Store cookies covered at room temperature for up to 1 week.


  1. Freezing Instructions: Baked and cooled cookies freeze well for up to 3 months. Unbaked cookie dough balls freeze well for up to 3 months too. Bake frozen cookie dough balls for an extra minute, no need to thaw. Click here for my tips and tricks on freezing cookie dough.
  2. You can use unsalted butter in this recipe. If so, add 1/4 teaspoon salt with the flour.
  3. Peanut Butter: While it’s great for cooking and eating, natural style peanut butter isn’t ideal for these cookies. They will turn out too dry and crumbly. I do not recommend crunchy style peanut butter for that same reason. I recommend processed creamy peanut butter such as Jif or Skippy.
  4. Use quick oats in this recipe. Quick oats are more finely cut whole oats and will give the monster cookies a more uniform texture. Furthermore, quick oats act more as a binder since the consistency is more powdery. If you don’t have quick oats, pulse your whole oats in the food processor a few times to break them down.
  5. Looking for a recipe without peanut butter? Here are my Chewy Oatmeal M&M Cookies.
  6. Why is everything at room temperature? All refrigerated items should be at room temperature so the batter mixes together easily and evenly. Read here for more information.
  7. Be sure to check out my top 5 cookie baking tips AND my 10 must-have cookie baking tools.

Keywords: cookies, oatmeal cookies, monster cookies

stack of monster cookies


  1. I made these cookies for my dad for xmas two years ago. They were definitely a favorite! I usually make 3-4 different types of cookies for him and these were gone first. You won’t be disappointed!

  2. Brittani Irish says:

    These are amazing. I also LOVE LOVE LOVE your Fudge Ripple Monster Bars from your ‘Baking Addiction’ recipe book . They are to die for!!!! I’m curious, have you ever tried freezing them? The bars that is. Do they freeze well? I’d love to do that but I’m afraid they won’t be as good.

    1. Hi Brittani! Thank you so much. Yes, they freeze wonderfully. Freeze squares between sheets of parchment paper for up to 3 months. Thaw in the refrigerator or at room temperature.

  3. I pinned this recipe ages ago and just now got around to making them. They are AMAZING!!! Seriously delicious, super rich, and soft cookies. We will definitely be making these again.

  4. I love love love this recipe. My cookies were perfect. Thank you for always posting the most precise recipes.

  5. I can’t eat oats. Is there anything that could be substituted for them?

    1. Hi Imelda, I recommend making my regular peanut butter cookies instead. You can swap the nuts and chocolate chips for M&Ms.

  6. Another winner! These are amazing. Easy to throw together and a crowd pleaser. Thank you! I improvised and used while chocolate chips instead of m&ms because I had none of those.

  7. Love love love these cookies! I love how thick they are, they are kind of filling so I definitely can’t have too many in one sitting which is good. Super easy to make. Im sure I will be making a lot of these in my future

  8. Jacinda Larson says:

    Can I substitute margarine for the butter to make these dairy free?

    1. Stephanie @ Sally's Baking Addiction says:

      We don’t recommend it, Jacinda. Best to stick with real butter, or try a vegan butter substitute such as Earth Balance brand (although we have not tested it in this recipe).

  9. This is the perfect recipe when you have a bunch of different kinds of chocolate chips/baking chips. I actually made these with whatever was in my candy bowl (I think it was a mix of reese’s pieces, pretzel m&ms and mini m&ms) and the bottom of some white chocolate chip and chocolate chunk bags. Perfect recipe to clean out the cabinets!

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