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

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

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!

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 (160g) 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. 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.
  4. Looking for a recipe without peanut butter? Here are my Chewy Oatmeal M&M Cookies.
  5. 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.
  6. 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

Monster Peanut Butter Cookies - the best monster cookies you'll ever make! @sallybakeblog


  1. Just made these-pretty good, but not the best Monster cookies I’ve ever made. I like recipes with more oatmeal and less or no flour. Also seem a little bland, maybe a little salt would help. Overall they are good, but not great.

  2. Excellent baking site! I’ve been a professional baker for 30 years and these are real recipes and done with professional techniques. The results are perfect.

  3. Ahhh! Such thick cookies! I could hardly believe my eyes when I saw this incredibly thick and soft cookies for the first time. Thick cookies are my favorite kind; the softer, the better, in most cases. But sadly, my brother has a very serious peanut allergy, so these peanut-butter and M&M-filled cookies aren’t possible for us :(. But, I would still love to have such an immensely thick cookie, so I thought I’d do a kind of super-thick chocolate hazelnut cookie. So, sub Nutella for the peanut butter and hazelnuts and more chocolate chips for the M&M’s. Would all that work? Thanks, Sally, I appreciate it!

    1. Nutella is a little thinner than the consistency of peanut butter, but you can try a 1:1 substitution. The cookies may not be as thick though!

    2. Wow! Wow! Wow! I don’t have words for these cookies. They are incredibly delicious. And SO thick! I have such a hard time getting my cookies to bake thick because of the high altitude that I live in (5000 ft). It boggled my mind that they came out so thick without even chilling. Thanks again for another incredible recipe Sally!

  4. Haven’t made these yet, wanted to ask, I had a monster cookie that was really good she said the recipe called for a tbsp of corn syrup.
    Having read just enough of your blog to think I knew something (ha..ha)
    I thought it was for more chew in the cookie. Wanted to know your thoughts. Thanks so much, your helping me to want to bake again.
    My favorite so far is you Oatmeal Raisin Cookies.

  5. Used unsalted butter which didn’t give enough flavor to the cookie – use salted butter as recipe says or add salt – after a day the cookies were very dry and crumbly – not sure why followed the recipe except for the salted butter.

  6. Quick, easy, and delicious! Made ahead and froze. Hand mixed and seemed to be ok. Used chunky peanut butter instead of creamy and liked the crunch. Could probably use other add ins like pecans etc. Was surprised how light colored they were. Had to refrain from baking longer. Will definitely make again!

    1. I’m so happy you enjoyed these monster cookies! This recipe is definitely a great base for add-ins of your choice! Would love to know what you try next time 🙂

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