Unleash a burst of flavor with these incredibly delicious Flourless Monster Cookie Bars! Packed with hearty oats, rich peanut butter, irresistible mini chocolate chips, and vibrant mini M&Ms, these bars are a dream come true for cookie lovers. They’re effortlessly easy to make, wonderfully fun to share, and absolutely bursting with scrumptious taste. Prepare to fall in love with your new favorite go-to treat!

Discover Your New Obsession: Flourless Monster Cookie Bars
If you’re anything like me, you harbor a deep affection for classic monster cookies. That perfect blend of creamy peanut butter, chewy oats, decadent chocolate chips, and those delightfully crunchy mini M&Ms is simply irresistible. Well, get ready for an even more amazing experience, because these Flourless Monster Cookie Bars take everything you love about monster cookies and elevate it to an entirely new level!
My obsession with these bars runs deep, and for good reason. They offer all the beloved flavors and textures of traditional monster cookies but in a convenient, mess-free bar form. The harmonious combination of savory peanut butter with sweet brown sugar, crunchy candies, and wholesome oats creates a symphony of taste that’s hard to beat. Each bite delivers a chewy, satisfying experience that will leave you craving more. Whether you’re a long-time fan of monster cookies or new to their magic, you absolutely must bake these flourless wonders immediately. Trust me, they’re going to become a staple in your recipe collection!

Essential Tip for Gluten-Free Baking: Choose Certified Oats
For those seeking a truly gluten-free treat, a crucial step in preparing these delicious monster cookie bars is selecting the right oats. While oats are naturally gluten-free, they are often processed in facilities that also handle wheat, barley, and rye. This can lead to cross-contamination, making them unsuitable for individuals with celiac disease or gluten sensitivities.
To ensure your Flourless Monster Cookie Bars are genuinely gluten-free, always opt for oats that are specifically labeled and certified gluten-free. This certification guarantees that the oats have been harvested, processed, and packaged in environments free from gluten-containing grains, offering peace of mind and a safe, delightful dessert experience for everyone. This simple substitution allows you to enjoy all the chewy goodness without any dietary concerns, making these bars a versatile and inclusive option for any gathering.
Baking Made Simple: Easier Than Traditional Cookies
One of the many reasons these Flourless Monster Cookie Bars are an absolute game-changer is their incredible ease of preparation compared to traditional drop cookies. Forget the tedious process of scooping individual portions, carefully spacing them on baking sheets, and enduring multiple batches in the oven. With these bars, you get all the delightful flavors and textures of monster cookies with a fraction of the effort.
The beauty of a cookie bar recipe lies in its simplicity: a single pan, one press, and you’re done! The dough comes together in mere minutes, requiring minimal fuss. There’s no chilling, no rolling, and no waiting. Just combine your ingredients, press the mixture evenly into your prepared baking dish, and let your oven do the rest. The natural stickiness of the peanut butter and the binding power of the oats work wonders, eliminating the need for flour or butter to hold everything together. The result? Thick, chewy, peanut butter oatmeal chocolate candy-loaded bars that are perfectly soft and incredibly satisfying. It’s truly a baker’s dream – maximum flavor with minimum effort. These bars are a testament to how simple and rewarding baking can be, proving that sometimes, the easiest recipes yield the most spectacular results.

Explore More Easy and Delicious Flourless Recipes
If you’ve fallen in love with the ease and incredible taste of these Flourless Monster Cookie Bars, you’re in for a treat! The world of flourless baking is vast and full of delightful surprises. These recipes prove that you don’t need traditional flour to create deeply flavorful, satisfying, and utterly delicious desserts. In fact, many flourless options offer a unique texture and richness that sets them apart.
Discover a treasure trove of other Easy and Delicious Flourless Recipes that are guaranteed to become new family favorites. From rich, fudgy brownies to moist cakes and decadent cookies, these flour-free alternatives are not only simpler to prepare but also often bring out the natural flavors of other ingredients like chocolate, nuts, and fruits even more intensely. Embrace the joy of baking without flour and expand your repertoire with treats that are perfect for any occasion, offering both convenience and exceptional taste. You’ll be amazed at how many incredible desserts you can create with just a few simple ingredient swaps.
The Ultimate Crowd-Pleaser: Perfect for Parties and Beyond
These Flourless Monster Cookie Bars are more than just a dessert; they’re a celebration in every bite, making them absolutely perfect for any gathering or occasion. The oats bake up beautifully, becoming wonderfully toasty while retaining a delightful chewiness that perfectly complements the creamy peanut butter, the warm sweetness of brown sugar, and the medley of chocolates and candies.
Imagine the smiles these vibrant bars will bring to your next party, potluck, or school event. They’re a guaranteed hit with both kids and adults, thanks to their familiar and much-loved monster cookie flavor profile in an easy-to-grab bar form. They also make an ideal after-school snack, providing a satisfying burst of energy and sweetness, or a truly indulgent nightly dessert to wind down your day. Every time I bake a batch (which, admittedly, has been quite frequently lately!), the irresistible aroma fills the kitchen, drawing everyone in. The hardest part is always waiting for them to cool down enough before we can finally slice into their glorious layers of goodness. Prepare for these bars to disappear quickly – they are simply that good!

Expand Your Baking Horizons: More of The Best Brownies and Bars
If the convenience and deliciousness of these Flourless Monster Cookie Bars have captivated you, then get ready to explore a whole universe of equally amazing treats! Our extensive collection of The Best Brownies and Bars is thoughtfully curated to offer something for every palate and every occasion.
Dive into a world of diverse textures and flavors, from intensely chewy and fudgy brownies that melt in your mouth, to nutty and chunky creations bursting with delightful surprises. Discover rich chocolatey delights, incredibly convenient no-bake options perfect for warm weather, and more innovative flourless recipes that defy expectations. Whether you’re looking for a quick treat, a stunning dessert to impress guests, or a comforting classic, this collection has it all. Each recipe is designed to be approachable, ensuring baking success and an abundance of joy in your kitchen. Prepare to find your next favorite dessert within this incredible assortment, guaranteed to satisfy every sweet craving.
Gather Your Ingredients: What You Need for Flourless Monster Cookie Bars
Creating these delightful Flourless Monster Cookie Bars is surprisingly simple, thanks to a straightforward list of readily available ingredients. You likely have many of these staples in your pantry already! The magic happens when these humble components come together to form a truly extraordinary dessert. Here’s what you’ll need to get started:
- Peanut Butter: Opt for creamy or crunchy (your preference!), ensuring it’s a “no-stir” variety for best results and consistency in the dough. This provides the essential rich, nutty base and helps bind the bars without flour.
- Brown Sugar: Adds deep, caramel-like sweetness and moisture, contributing to the chewy texture.
- Vanilla Extract: A crucial flavor enhancer that complements the peanut butter and chocolate beautifully.
- Large Eggs: Act as a binding agent, providing structure and richness to the bars.
- Old-Fashioned Rolled Oats: The star of our flourless recipe, providing a hearty, chewy texture. Remember to choose certified gluten-free oats if you need a gluten-free option.
- Baking Soda: Helps the bars achieve a slight lift and a tender crumb.
- Kosher Salt: Balances the sweetness and enhances all the flavors, especially the peanut butter and chocolate.
- Mini Chocolate Chips: These tiny morsels melt into pockets of pure chocolatey bliss throughout the bars.
- Mini M&M Candies: Provide vibrant color, a delightful crunch, and that unmistakable candy-coated chocolate flavor that defines “monster.”
- 9×13 Baking Dish: The perfect size for baking a generous batch of bars.
- Parchment Paper: Essential for easy removal of the bars from the dish and stress-free cleanup.
- Nonstick Cooking Spray: Provides an extra layer of nonstick protection, especially for those chewy, sticky edges.
With these ingredients at hand, you’re just a few steps away from baking a batch of these irresistible flourless delights!

Baking Guide: How to Make Flourless Monster Cookie Bars
Get ready to create a batch of the most satisfying cookie bars you’ve ever tasted! The process for making these Flourless Monster Cookie Bars is wonderfully straightforward, promising delicious results with minimal fuss. Follow these simple steps, and you’ll have warm, chewy bars ready to enjoy in no time.
- Step 1: Prepare Your Baking Dish. Begin by preheating your oven to 350°F (175°C). This ensures the oven is at the optimal temperature for even baking from the moment your bars go in. Line a 9 x 13-inch baking dish with parchment paper, leaving an overhang on the sides. This overhang will act as “handles” later, making it incredibly easy to lift the entire slab of baked bars out of the pan. Give the parchment paper a light spray with non-stick cooking spray for extra insurance against sticking. Set your prepared dish aside.
- Step 2: Cream Peanut Butter and Sugar. In the spacious bowl of an electric mixer (fitted with the paddle attachment), combine the peanut butter and brown sugar. Beat these two ingredients together on medium speed until the mixture is smooth, creamy, and well combined. This process incorporates air and creates a light, fluffy base for your cookie bars.
- Step 3: Incorporate Wet Ingredients. Next, add the vanilla extract to the peanut butter mixture, beating until fully incorporated. Then, add the large eggs, one at a time. It’s important to beat well after each addition to ensure each egg is fully integrated, which helps with the texture and binding of the dough. Scrape down the sides of the bowl as needed to ensure everything is evenly mixed.
- Step 4: Add Dry Ingredients. Reduce the mixer speed to low. Add the old-fashioned rolled oats, baking soda, and kosher salt to the bowl. Mix on low speed until the dry ingredients are just combined with the wet mixture. Be careful not to overmix; overmixing can lead to tougher bars.

- Step 5: Fold in the Fun. Once the base dough is just combined, it’s time for the signature monster cookie additions! Gently fold in the mini chocolate chips and mini M&M candies using a spatula or by mixing briefly on the lowest speed. Ensure they are evenly distributed throughout the dough, so every bite is packed with deliciousness.
- Step 6: Press into Pan. Transfer the dough mixture into your prepared 9×13-inch baking dish. The dough might appear crumbly at this stage, but don’t worry! Use the back of a spoon, your hands (lightly greased if it’s too sticky), or a flat-bottomed glass to press the mixture down firmly and evenly into the pan. Make sure it reaches all corners and forms a compact, uniform layer. This ensures consistent baking and perfectly structured bars.

- Step 7: Bake to Golden Perfection. Place the baking dish into your preheated oven. Bake for approximately 30 minutes, or until the top of the bars turns a beautiful golden brown and the edges are set. The center might still look slightly soft, but it will firm up as it cools. Avoid overbaking to maintain their wonderfully chewy texture.

- Step 8: Cool and Slice. Once baked, carefully remove the pan from the oven. This step requires patience, but it’s essential for perfectly structured bars. Let the bars rest in the baking dish for at least 15 minutes before attempting to slice into them. Cooling allows the bars to set properly, preventing them from crumbling. After initial cooling, you can lift the entire slab of bars out using the parchment paper overhang and transfer them to a wire rack to cool completely before slicing into individual squares. Enjoy your homemade, flourless monster cookie bars!

Storage Solutions: Keeping Your Flourless Monster Cookie Bars Fresh
You’ve just baked a batch of incredibly delicious Flourless Monster Cookie Bars, and now you want to make sure they stay fresh and enjoyable for as long as possible. Proper storage is key to maintaining their delightful chewy texture and vibrant flavors. Here’s how to store them for both short-term enjoyment and long-term convenience:
To Store Cookie Bars for Up to Five Days:
- In the Baking Dish: If you plan to enjoy them within a few days, you can simply leave the bars in the original 9×13-inch baking dish. Once they are completely cooled, cover the dish tightly with plastic wrap or aluminum foil. This helps to prevent air exposure, which can dry out the bars.
- In an Airtight Container: For a more organized approach or if you need to transport them, cut the cooled bars into individual squares. Place them in an airtight container. Layering them with small sheets of parchment paper between layers can help prevent sticking, especially if the bars are still slightly warm or if your climate is humid. Store the container at room temperature on your counter. They will remain wonderfully fresh and chewy for up to five days.
To Freeze Cookie Bars for Longer Enjoyment:
Freezing these bars is an excellent option for meal prep or saving a treat for a future craving. Properly frozen, they can last for several months!
- Prepare for Freezing: Ensure the bars are completely cooled before freezing. Warm bars will create condensation, leading to ice crystals and potential freezer burn.
- Individual Wrapping (Optional but Recommended): For maximum freezer burn protection and ultimate convenience, wrap each individual bar tightly in plastic wrap. This extra step provides a robust barrier against air and moisture.
- Container Storage: Place the wrapped (or unwrapped, if skipping individual wrap) bars into a freezer-safe baggie or an airtight freezer-safe container. If placing unwrapped bars directly into a container, add a sheet of parchment paper between each layer to prevent them from sticking together.
- Thawing: When you’re ready to enjoy a frozen monster cookie bar, simply remove it from the freezer. Thaw loosely covered at room temperature for several hours. This gradual thawing helps retain their texture. You can also briefly warm them in the microwave for a few seconds for a freshly baked feel.
By following these storage tips, you can ensure that every bite of your Flourless Monster Cookie Bars is as delicious as the first, whenever you choose to indulge!

We hope you thoroughly enjoy baking and devouring these incredible Flourless Monster Cookie Bars! They are truly a special treat that brings smiles to every face. If you make this recipe, don’t forget to snap a picture and share your delicious creations with me. Tag me on Instagram @thebakermama so I can see how inspired and creative you get with the recipes I share. Your culinary adventures brighten my day!
Happy baking, and enjoy every delightful bite!
xoxo,

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Flourless Monster Cookie Bars
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Author: Maegan – The BakerMama
Prep Time: 10 mins
Cook Time: 30 mins
Total Time: 35 mins
Yield: 18 bars
Category: Dessert, Cookie Bar
Description
Bake these incredibly tasty Flourless Monster Cookie Bars, a perfect blend of hearty oats, creamy peanut butter, delightful mini chocolate chips, and vibrant mini M&Ms. This easy-to-follow recipe promises a fun baking experience and results in an oh-so-yum dessert that’s great for any occasion, especially for those seeking gluten-free options!
Ingredients
- 2 cups creamy or crunchy peanut butter (no-stir recommended)
- 1 cup packed light brown sugar
- 2 teaspoons pure vanilla extract
- 2 large eggs
- 2 and 1/2 cups old-fashioned rolled oats (certified gluten-free for GF option)
- 1 teaspoon baking soda
- 1 teaspoon kosher salt
- 1 cup mini semi-sweet chocolate chips
- 1 cup mini M&M candies
Instructions
- Preheat oven to 350°F (175°C). Line a 9 x 13-inch baking dish with parchment paper, allowing some overhang for easy removal. Spray the parchment with non-stick cooking spray and set aside.
- In the bowl of an electric mixer fitted with the paddle attachment, beat the peanut butter and brown sugar until light and smooth. Add the vanilla extract and beat until combined. Then, add the eggs, one at a time, beating well after each addition until fully incorporated and creamy.
- Reduce mixer speed to low. Add the rolled oats, baking soda, and kosher salt to the mixture. Mix until just combined, being careful not to overmix. Once combined, gently fold in the mini chocolate chips and mini M&Ms using a spatula or on very low speed.
- Press the cookie dough mixture evenly into the prepared baking dish. The dough may be a bit crumbly, but press it firmly and consistently into the pan, ensuring a compact layer from edge to edge.
- Bake for 30 minutes, or until the top of the bars turns a beautiful golden brown and the edges are set. The center may appear slightly soft but will firm up as it cools.
- Remove the pan from the oven and allow the bars to rest and cool in the dish for at least 15 minutes before carefully lifting them out by the parchment paper overhang. Transfer the slab of bars to a wire rack to cool completely before slicing into individual squares.
