These flourless monster monster cookie bars may not have flour, but they’re loaded with oatmeal and peanut butter. They’re gluten free and so easy to make!

flourless monster cookie bars

Have you ever had a monster cookie?! They are all of your favorite cookie ingredients combined to make one super epic flavor. Hence, the monster part! And now we’ve got a flourless monster cookie bars recipe for you!

These monster cookie bars are no exception. But the only thing not loaded into these is flour. They’re chewy bars are made with oats and peanut butter only! They stay together with the combination of peanut butter, oats and eggs mostly.

Oh, and NO BUTTER either! The only butter in this recipe is peanut butter.

monster cookie bars

How to make monster cookie bars:

To make monster cookie bars, you’ll start by combining the eggs, peanut butter, sugar and vanilla to a bowl. Use a whisk to combine it all then add the oats and baking soda. Stir in mini M&Ms and chocolate chips then dump it all into 9×9 pan lined with parchment.  Spread it evenly to the corners then you’re ready to bake!

How long to bake monster cookie bars:

Bake these flourless monster cookie bars for 18-22 minutes at 350°F. Start watching the bars at 18 minutes and remove when they start to get brown on the top.

You’ll know they’re done when a toothpick inserted in the center comes out clean!

When you take them out of the oven, allow them to cool all the way in the pan. You can cut them when they’re still a little warm, but you’ll want to wait at least 30 minutes so they set a little more. You can eat them right away or store them for later!

no flour monster cookie bars

How to store flourless monster cookie bars:

Flourless monster cookie bars are best stored in an airtight container at room temperature for 3 days. You can also store them in the fridge for up to one week or in the freezer for up to 3 months!

These flourless monster cookie bars are such a fun recipe to make with kids! I have a feeling your kiddos will think they’re pretty fun to eat too! You could even swap out the regular M&Ms for a seasonal flavor to make them festive, like pumpkin spice or the Easter ones!

monster cookie bar recipe

I hope you love this recipe as much as I do! If you love this recipe give me a virtual high five by following @OhSweetBasil and myself at @What_MollyMade on Instagram! Be sure to tag us so we can see your creations!

More gluten free cookies:

  • Flourless monster cookies
  • Gluten Free Chocolate Marshmallow Cookies
  • Gluten Free Chocolate Chip Peanut Butter Blondies

Flourless Monster Cookie Bars

4.31 from 26 votes
Servings: 12
Prep Time: 15 minutes
Cook Time: 25 minutes
Total Time: 40 minutes


These flourless monster monster cookie bars may not have flour, but they’re loaded with oatmeal and peanut butter. They’re gluten free, so chewy and so easy to make!


  • 2 Eggs , plus 1 egg yolk
  • 1 Cup Peanut Butter, creamy, I used JIF
  • 3/4 Cup Brown Sugar, light, packed
  • 1/4 Cup Granulated Sugar
  • 2 teaspoons Vanilla Extract
  • 1 Cup Oats , old fashioned, use gluten-free oats for GF option
  • 1/2 teaspoon Baking Soda
  • 1/2 teaspoon Salt
  • 1/2 Cup Candy, Mini M&Ms
  • 1/2 Cup Chocolate Chips, mini semisweet


  • Preheat oven to 350°F and line a 9x9 inch baking pan with parchment paper. Set aside. 
  • Using a large mixing bowl, add the eggs, creamy peanut butter, light brown sugar, granulated sugar and vanilla extract. Stir together until combined using a rubber spatula, whisk or wooden spoon. Once combined, add the oats, baking soda and salt and mix well. Then add the M&Ms and chocolate chips and mix well until combined. Dough will be thick and grainy from the sugar.
    2 Eggs, 1 Cup Peanut Butter, 3/4 Cup Brown Sugar, 1/4 Cup Granulated Sugar, 2 teaspoons Vanilla Extract, 1 Cup Oats, 1/2 teaspoon Baking Soda, 1/2 Cup Candy, 1/2 Cup Chocolate Chips, 1/2 teaspoon Salt
  • Scoop the dough into the prepared baking sheet and spread the dough evenly to the corners of the pan. Bake in the preheated oven for 18-22 minutes.
  • Start checking at 18 minutes to avoid over-browning. Remove from the oven and allow the cookie bars to cool all the way in the pan before cutting.
  • Sore in an airtight container at room temperature for 3 days, in the refrigerator for up to a week or in the freezer for up to 3 months. 


These cookie bars can be stored at room temperature for 3-4 days.


Serving: 1gCalories: 314kcalCarbohydrates: 38gProtein: 8gFat: 16gSaturated Fat: 5gCholesterol: 30mgSodium: 267mgPotassium: 192mgFiber: 2gSugar: 30gVitamin A: 76IUCalcium: 47mgIron: 1mg
Author: WhatMollyMade
Course: 100 Best Brownies and Bars Recipes

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A batch of flourless monster cookie bars