Gluten-Free Monster Cookie Bars

Our Gluten-Free Monster Cookie Bars recipe is everything you love about classic monster cookies in bar form! Made with a soft peanut butter oatmeal cookie base, they’re packed with m&ms and chocolate chips in every delicious bite!

Gather Your Ingredients

One of the things that makes this easy recipe such a crowd pleaser is the simple ingredients list. Let’s take a look!

How To Make Gluten-Free Monster Cookie Bars, Step By Step

As always, you can find the full recipe, with ingredient amounts, detailed instructions, and tips in the recipe card below.

1. Preheat & Prep. To Start, preheat oven temperature to 350 degrees F. Line a metal 9×13 pan with parchment paper and set aside.
2. Combine Dry Ingredients. In a medium bowl, combine gluten-free flour, gluten-free oats, quick oats, baking soda, and salt. Whisk to combine until evenly blended and fluffy. Set aside.
3. Cream Butter & Sugar. In a stand mixer (or large mixing bowl), combine softened butter, brown sugar, and granulated sugar. Beat on medium speed 2-3 minutes with the paddle attachment (or a handheld electric mixer) until the mixture is light, fluffy, and creamy. Scrape down the sides of the bowl.
4. Build The Dough. Mix in the peanut butter until fully incorporated. Add eggs, one at a time, followed by the egg yolk, and the vanilla. Scrape down the sides of the bowl. Add the dry ingredients, and mix until just a few dry patches remain.

5. Add Mix-Ins. Then, add 1 1/4 cups mini M&Ms, and 1 1/4 cups chocolate chips to the dough. Stir the mix-ins in by hand with a spatula (so you don’t break the M&Ms), until the dough is well blended and the goodies are well distributed.
6. Bake Cookies. Spread cookie dough out into the prepared pan and smooth into an even layer with an offset spatula. Bake 25-30 minutes, or until the cookie bars look golden brown on top and just set in the center. (Try not to overbake, or the bars will be dry and cakey rather than fudgy and soft. Keep in mind that the cookie bars will continue to bake and set as they cool.)
7. Immediately Add Topping. As soon as the cookie bars come out of the oven, sprinkle the extra mini M&Ms and the mini chocolate chips on top while they cookie bars are still hot from the oven. Place the pan on a wire rack and let cookie bars cool completely before slicing. (Chilling the cookie bars first will give you the neatest slices!)
8. Serve & Store. When cookie bars have cooled completely, cut into slices & enjoy! Store leftover cookies in an airtight container at room temperature 2-3 days, or freeze up to 2 months.

FAQ + Tricks For The Best Monster Cookie Bars

Your Pan Material Matters! If you’re using a glass or ceramic baking pan instead of a metal pan, keep in mind that you’ll likely need to add a few minutes to the bake time, and your bars may “climb” the sides a bit. We like this metal 9×13 pan–it bakes the bars to the perfect thickness and conducts heat gently and evenly for a beautifully even bake.

Can I Use Natural Peanut Butter? While natural peanut butter is great for sandwiches and toast, I do not recommend it for monster cookie bars, as it tends to make the cookie bars dry out faster, and can impact the texture. For best results, use a traditional peanut butter spread, like JIF or Skippy.

Can I Make These Dairy-Free? These monster cookie bars can be made dairy-free with a few simple swaps. First, use vegan butter (like Earth Balance) and dairy-free chocolate chips (like Guittard or Enjoy Life). Then, you’ll use dairy-free chocolate candies in place of the m&ms. We’ve had good luck with YumEarth Choco Yums and Unreal Candies.

More Mix-Ins To Try! Next time you’re looking to mix things up, try adding half chocolate chips + half peanut butter chips, or swap out the m&ms for reese’s pieces!

More Gluten-Free Cookie Bar Recipes To Try

Gluten-Free S’mores Bars

Gluten-Free Oatmeal Fudge Bars

Gluten-Free Sugar Cookie Bars

Gluten-Free Brookies

Gluten-Free Monster Cookie Bars

5 from 1 vote

Author: Emily Dixon, Sweets & Thank You

Our Gluten-Free Monster Cookie Bars recipe is everything you love about classic monster cookies in bar form! Made with a soft peanut butter oatmeal cookie base, they're packed with m&ms and chocolate chips in every delicious bite!

Prep Time: 20 minutes minutes

Cook Time: 30 minutes minutes

Total Time: 50 minutes minutes

Print Pin Rate

Servings: 20 Cookie Bars

Ingredients

Dry Ingredients:

• 1 ¾ cup gluten-free measure-for-measure flour* (210 grams)
• 1 cup gluten-free rolled oats (or more quick oats)*
• ½ cup gluten-free quick oats (or more rolled oats)*
• 1 teaspoon baking soda
• ½ teaspoon kosher salt

Wet Ingredients:

• 1 cup butter, softened (226 grams)
• 1 ¼ cup light brown sugar (250 grams)
• ⅓ cup granulated sugar (66 grams)
• 1 cup creamy peanut butter*
• 2 large eggs room temperature
• 1 egg yolk room temperature
• 1 Tablespoon vanilla extract

Mix-Ins & Toppings:

• 1 ¼ cups mini M&Ms for the cookie dough
• 1 ¼ cups semisweet chocolate chips for the cookie dough
• ¼ cup mini M&Ms for topping the cookies
• ¼ cup mini chocolate chips for topping the cookies

Instructions

• Preheat & Prep. To Start, preheat oven temperature to 350 degrees F. Line a metal 9×13 pan with parchment paper and set aside.
• Combine Dry Ingredients. In a medium bowl, combine gluten-free flour, gluten-free oats, quick oats, baking soda, and salt. Whisk to combine until evenly blended and fluffy. Set aside.
• Cream Butter & Sugar. In a stand mixer (or large mixing bowl), combine softened butter, brown sugar, and granulated sugar. Beat on medium speed 2-3 minutes with the paddle attachment (or a handheld electric mixer) until the mixture is light, fluffy, and creamy. Scrape down the sides of the bowl.
• Build The Dough. Mix in the peanut butter until fully incorporated. Add eggs, one at a time, followed by the egg yolk, and the vanilla. Scrape down the sides of the bowl. Add the dry ingredients, and mix until just a few dry patches remain.
• Add Mix-Ins. Then, add 1 1/4 cups mini M&Ms, and 1 1/4 cups chocolate chips to the dough. Stir the mix-ins in by hand with a spatula (so you don't break the M&Ms), until the dough is well blended and the goodies are well distributed.
• Bake Cookies. Spread cookie dough out into the prepared pan and smooth into an even layer with an offset spatula. Bake 25-30 minutes, or until the cookie bars look golden brown on top and just set in the center. (Try not to overbake, or the bars will be dry and cakey rather than fudgy and soft. Keep in mind that the cookie bars will continue to bake and set as they cool.)
• Immediately Add Topping. As soon as the cookie bars come out of the oven, sprinkle the extra mini M&Ms and the mini chocolate chips on top while they cookie bars are still hot from the oven. Place the pan on a wire rack and let cookie bars cool completely before slicing. (Chilling the cookie bars first will give you the neatest slices!)
• Serve & Store. When cookie bars have cooled completely, cut into slices & enjoy! Store leftover cookies in an airtight container at room temperature 2-3 days, or freeze up to 2 months.

Notes

• Gluten-Free Flour. We love and recommend King Arthur Measure For Measure Gluten-Free Flour for these monster cookie bars. If you use another 1:1 gluten-free flour blend, be sure it contains xanthan gum! We highly recommend weighing the flour (and other dry ingredients) for the best results, but if you don’t have a kitchen scale, we recommend using the scoop and level method to avoid packing too much flour into the measuring cup.
• Peanut Butter. Do NOT use natural peanut butter for these cookie bars, or they’ll dry out faster. Use a traditional peanut butter spread, like JIF or Skippy, for best results.
• Oats. If needed, you can use all rolled oats or all quick oats for these cookies. I just love the texture you get from using a mix!
• Toppings: I love the look of mini m&ms and mini chocolate chips on top of the cookie bars. You can use traditional M&Ms and chocolate chips, though your cookie bars will look different from mine.

Video

Course: Dessert

Cuisine: American

Diet: Gluten Free

Keyword: gluten-free monster cookies, monster cookie recipe

Find the recipe:

sweetsandthankyou.com/monster-cookie-bars/