Bake these tasty Flourless Monster Cookie Bars that are loaded with oats, peanut butter, mini chocolate chips and mini M&Ms. Easy, fun and oh so yum!!

I have a slight obsession with monster cookies & mini M&Ms & peanut butter & oats & pretty much everything that is these monster cookie bars! If you love monster cookies, you’ve gotta bake these ASAP. You’re going to love them!

They’re basically an easier version of monster cookies because they’re baked in bar form. No rolling, spacing or baking in batches until all the dough has been used. Just press and bake!

Thick, chewy bars of peanut butter oatmeal chocolate candy loaded goodness. What’s not to love?!

The dough comes together in no time and unlike most cookie bar recipes, the oatmeal and peanut butter are doing most of the work. No flour or butter getting in their way!

The dough will appear crumbly, but trust me, trust me!, it presses perfectly into the pan…

Then just 30 minutes in the oven for all the yumminess to come together…

The kind of bars that will bring all the kids to the kitchen (and adults too!). Every time I bake these (which has been quite often here lately!), we can hardly wait to slice into them…

The oats are toasty yet hold their chew and compliment the flavor of the peanut butter, brown sugar and chocolates so well.

These monster cookie bars are great to bake for parties, after-school snack and of course, nightly dessert! Enjoy!


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Flourless Monster Cookie Bars

  • Author: Maegan - The BakerMama
  • Prep Time: 5 mins
  • Cook Time: 30 mins
  • Total Time: 35 mins
  • Yield: 18 1x
  • Category: Dessert


Bake these tasty Flourless Monster Cookie Bars that are loaded with oats, peanut butter, mini chocolate chips and mini M&Ms. Easy, fun and oh so yum!!


  • 2 cups creamy or crunchy peanut butter
  • 1 cup brown sugar
  • 2 teaspoons vanilla
  • 2 large eggs
  • 21/2 cups old-fashioned rolled oats
  • 1 teaspoon baking soda
  • 1 teaspoon kosher salt
  • 1 cup mini chocolate chips
  • 1 cup mini M&M candies


  1. Preheat oven to 350°F. Line a 9 x 13-inch baking dish with parchment paper and spray with non-stick cooking spray. Set aside.
  2. In the bowl of an electric mixer fitted with the paddle attachment, beat the peanut butter and brown sugar until smooth. Add the vanilla and then the eggs, one at a time, beating until well incorporated.
  3. Add the oats, baking soda and salt and mix on low speed until just combined. Stir in the chocolate chips and M&Ms.
  4. Press mixture evenly into prepared baking dish. The dough will be crumbly at this point, but it should press perfectly into the pan.
  5. Bake for 30 minutes or until the top of the bars starts to turn golden brown.
  6. Remove from oven and lest rest for at least 15 minutes before slicing into.


About The BakerMama

Maegan is the author of her best-selling Beautiful Boards, Spectacular Spreads and Brilliant Bites cookbooks. She started blogging in 2012 and features hundreds of original recipes on The BakerMama. She truly enjoys sharing her easy, family-friendly recipes, creative meal ideas, food board creations, and entertaining spreads to encourage others to get in the kitchen and make something memorable for their loved ones to enjoy together. Learn More

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  1. Mine turned out super dry. Not sure why as i followed the recipe. Only difference is I used a natural peanut butter but it was stirred up good

    1. Hi Ashley! It sounds like your natural peanut butter or brown sugar might have been dried out. Next time, if you notice the batter is dry before baking, add some more peanut butter. Hope this helps and that you’re able to try them again soon.

    1. Hi Jill! Yes, just make sure you stir the peanut butter well to incorporate the oil before measuring it out to add to the recipe. Enjoy!

      1. Isn’t Nutella a nut based ingredient (hazelnut)? Grandson allergic to all tree nuts, not just peanuts….what is cookie butter……it is the same as unsalted butter?

      2. Hi Arlene! Nutella is made of hazelnuts which is a tree nut. Peanuts are not tree nuts. Cookie butter is made with cookie crumbs so there’s usually no nuts in it. It has a similar texture to peanut butter. Very different from regular butter. Hope this helps!

  2. Can you use a regular blender if you don’t have a standing mixer? Or should I just hand mix all the ingredients?

    1. Hi Rochelle! I wouldn’t recommend using a blender as you don’t want the ingredients to be too blended together. Mixing with a handheld electric mixer or with a sturdy spoon should work great. Enjoy!

  3. These look delicious! All your recipes just make me happy, lol. They’re so simple and yummy looking! Thanks for all you do for your readers 😉