Decadent Brown Butter Oatmeal Cookie Bars with Salted Nutella Swirl: Your Ultimate Sweet & Salty Treat

Prepare yourself for a truly extraordinary dessert experience! While classic oatmeal chocolate chip cookies hold a special place in our hearts, these Brown Butter Oatmeal Cookie Bars with a Salted Nutella Swirl elevate the beloved treat to an entirely new level. Forget everything you thought you knew about cookie bars; these are richer, chewier, and impossibly delicious, combining the depth of brown butter with the irresistible allure of Nutella and a hint of flaky sea salt.

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If you’re as much a fan of rich, chewy dessert bars as I am, you’ll adore this recipe. These bars are an absolute dream for any occasion, from casual family gatherings to festive holiday celebrations. And if you love this decadent oatmeal cookie bar recipe, be sure to also try my Triple Chocolate Pecan Brownies, my Spiced Banana Cake with Brown Butter Cream Cheese Frosting, and these delightful Biscoff Blondies with White Chocolate!

Why These Nutella Oatmeal Cookie Bars Are Simply the Best

It might be a mouthful to say “Brown Butter Oatmeal Cookie Bars with Salted Nutella Swirl,” but every word in that title promises an explosion of flavor and texture that you simply have to experience. This recipe delivers everything you could possibly want in a dessert bar: chewiness, rich flavor, and a perfect balance of sweet and salty. These bars aren’t just good; they’re an unforgettable indulgence!

What makes them stand out? They begin with a remarkably easy, one-bowl oatmeal cookie dough. But this isn’t just any cookie dough – it’s infused with the deep, nutty essence of brown butter, the caramel notes of brown sugar, and a hint of warm cinnamon. This foundation creates a cookie bar that’s inherently flavorful and moist.

Once the dough is perfectly spread into your pan, it gets a luxurious treatment: a generous swirl of warmed Nutella chocolate-hazelnut spread. This adds a creamy, dreamy layer of chocolatey, nutty goodness that’s evenly distributed throughout each bite. After baking to golden perfection, a sprinkle of flaky sea salt provides that crucial contrasting element, cutting through the sweetness and enhancing every single flavor. The result is an easy-to-make, supremely decadent treat that will have everyone reaching for more!

Choosing the Right Oats for Perfect Texture

When it comes to oatmeal cookie bars, texture is paramount. This is why I strongly recommend against using quick-cooking or instant oats. While convenient for breakfast, these types of oats are heavily processed and will lose most of their structure and chewiness during baking, resulting in a mushy texture in your bars.

For these cookie bars, you absolutely want to use old-fashioned rolled oats. These oats retain their shape and provide a delightful chewiness that contrasts beautifully with the creamy Nutella swirl. You can typically find old-fashioned oats in large cylindrical containers in the breakfast aisle of any supermarket, or you can easily purchase them online. Trust me, the extra texture from old-fashioned oats is essential for these delectable oatmeal cookie bars!

Now that we’ve discussed the importance of brown butter and the right kind of oats, let’s gather the rest of the essential ingredients needed to create this truly special treat:

Essential Ingredients for Your Oatmeal Nutella Bars

• Brown Butter: As highlighted earlier, this is the star ingredient that infuses a rich, nutty depth into the cookie bars. It perfectly complements the hazelnut notes in the Nutella. If you opt for unsalted butter, remember to add ½ teaspoon of salt to your dry ingredients to achieve a balanced flavor. Don’t forget to check out my full guide on how to brown butter for detailed instructions!
• Brown Sugar: This provides moisture, a lovely caramel flavor, and contributes to the signature chewy texture of the bars. Feel free to use either light or dark brown sugar, or do as I often do and use a delightful mix of both for an even more complex flavor.
• Eggs: Ensure your eggs are at room temperature. This helps them incorporate more smoothly into the batter, creating a more uniform dough, and prevents them from chilling the brown butter and sugar mixture too much.
• Vanilla Extract: Use a high-quality pure vanilla extract. Vanilla plays a crucial supporting role, enhancing both the nutty notes from the brown butter and the rich flavors in these oatmeal cookie bars. Don’t skimp on good vanilla!
• Old-Fashioned Oats: As discussed, these are crucial for providing the best texture. They hold their shape and deliver that satisfying chewiness we all love in an oatmeal cookie bar.
• All-Purpose Flour: Accuracy in measuring flour is key for perfect baked goods. For best results, measure your flour by weight using a kitchen scale. If you don’t have one, use the spoon-and-level method to avoid over-packing.
• Baking Powder: This leavening agent gives a subtle lift to the cookie bars, preventing them from being too dense while maintaining their delightful chew.
• Cinnamon: While optional, a touch of ground cinnamon adds a warm, inviting spice note that beautifully harmonizes with the brown butter, chocolate, and hazelnut flavors. It adds an extra layer of complexity that is truly wonderful.
• Nutella: Or your preferred chocolate-hazelnut spread. We’ll gently warm it to achieve a pourable consistency, making it easy to swirl into the cookie dough for that irresistible marble effect. If you’re a true chocolate enthusiast, you might also enjoy my Hot Chocolate Mug Cake!
• Flaky Sea Salt: Another optional but highly recommended ingredient. A generous sprinkle of flaky sea salt on top provides a sensational sweet-and-salty contrast that elevates the flavors of the rich Nutella and buttery cookie.

Essential Equipment for Easy Baking

Good news! You don’t need any fancy gadgets to whip up these easy oatmeal cookie bars. Most of these items are probably already in your kitchen. Here’s what you’ll want to have on hand:

• A 9×9 square baking pan: This is the ideal size for perfectly thick and chewy bars.
• A whisk and a rubber spatula: For mixing and folding ingredients effectively.
• A large mixing bowl: To comfortably combine all your dough ingredients.
• A light-colored sauté pan (if possible): Light-colored pans make it easier to monitor the browning process of the butter, preventing it from burning.

And that’s pretty much it! With these simple tools, you’ll be ready to create a truly delicious treat.

Tips for Perfectly Baked Oatmeal Cookie Bars

• Don’t Rush the Brown Butter: Patience is key when browning butter. Keep a close eye on it and stir frequently to prevent burning. The reward is a deep, nutty flavor that’s well worth the effort.
• Room Temperature Eggs: This detail might seem small, but using room temperature eggs helps them emulsify better with the butter and sugar, leading to a smoother, more uniform dough.
• Avoid Overmixing: Once you add the dry ingredients, mix just until combined. Overmixing can develop the gluten in the flour, resulting in tougher bars. A tender crumb is what we’re after!
• Evenly Spread Dough: For uniform baking, ensure the cookie dough is pressed evenly into the pan. You can use a spatula or lightly floured hands.
• Warm Nutella for Easy Swirling: Heating the Nutella briefly makes it more liquid, allowing for beautiful, easy swirls. Don’t overheat it, just enough to make it pourable.
• Don’t Overbake: Cookie bars can go from perfectly baked to dry in a matter of minutes. The bars are ready when the edges are set and a toothpick inserted into the center comes out with moist crumbs, not wet batter. They will continue to set as they cool.
• Cool Completely Before Cutting: It’s tempting to cut into these warm, but cooling them completely allows them to firm up, making for cleaner cuts and a better texture.

Related Recipes: More Irresistible Dessert Bars and Cookies

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