I test a lot of cookie recipes, and these Brown Butter Chocolate Chip Hazelnut Cookie Bars are the ones I keep coming back to when I want something reliably nostalgic and slightly grown-up. The brown butter adds that toasty, caramel-like backbone that makes chocolate sing, and the toasted hazelnuts give each bite a quiet, buttery crunch. They slice cleanly, travel well, and stay satisfying for days.
There’s a simple rhythm to these bars: brown the butter, mix, fold in chocolate and hazelnuts, press into a pan, and bake. No fuss with chilling or scooping perfect rounds. You’ll want a 9×13 pan and a little attention when browning the butter, but the payoff is immense—deep, nutty flavor and a soft, chewy interior bordered by lightly crisped edges.
Below you’ll find a practical shopping guide, the exact ingredients and steps as written, and focused tips to help you get the texture and flavor you want. If you like chocolate chip cookies with an extra layer of flavor and a bar form that’s easy to serve, these are going to be a new favorite.
Your Shopping Guide
Before you start, gather everything on your list so you can move through the recipe without interruption. The browning step is the most delicate part of the process, so make sure your butter is fresh and your hazelnuts are ready for either roasting or using if pre-roasted. If you’ll be making the hazelnut skins removal step yourself, a tea towel and a rimmed baking sheet will be helpful.
- 9×13-inch baking pan — important for even thickness; the recipe is calibrated for this size.
- Nonstick cooking spray — quick release and helps prevent edges from sticking.
- Small saucepan — for browning the butter; a light-colored pan makes it easier to see the color change.
- Heatproof bowl — to cool the butter safely once it’s browned.
- Stand mixer or hand mixer — speeds the mixing of sugars and eggs, but you can mix by hand if needed.
- Spatula — for smoothing the dough evenly in the pan.
- Wire rack — cools the bars for clean slicing and prevents sogginess.
- Sharp knife or bench scraper — for cutting clean squares once cooled.
Ingredients
- 2 1/8cupsall-purpose flour — provides structure; measure carefully (spoon and level) to avoid dry, cakey bars.
- 1/2teaspoonsea salt — balances sweetness; used in the dough rather than just on top.
- 1/2teaspoonbaking soda — gives a modest lift and chew; don’t substitute baking powder here.
- 12tablespoonsunsalted butter — browned for nutty depth; use unsalted so you control final salt level.
- 1cuppacked brown sugar — adds moisture and caramel notes; packed to the level called for.
- 1/2cupgranulated sugar — balances the brown sugar and helps set the edges.
- 2large eggs — bind and give richness; room temperature for best incorporation.
- 2teaspoonsvanilla extract — flavor enhancer; use pure vanilla if possible.
- 2cupssemi-sweet chocolate chips — chocolate pockets throughout; semi-sweet balances the brown butter and hazelnuts.
- 3/4cupchopped hazelnutsskins removed — for crunch and flavor; chop to a uniform size so distribution is even.
- Sea saltfor sprinkling over cookie bars — a light finish; use flakes for a quick crunch and salty pop.
Step-by-Step: Brown Butter Chocolate Chip Hazelnut Cookie Bars
- Preheat the oven to 325°F. Spray a 9×13-inch baking pan with nonstick cooking spray and set aside.
- In a medium bowl, whisk together 2 1/8 cups all-purpose flour, 1/2 teaspoon sea salt, and 1/2 teaspoon baking soda. Set aside.
- Brown the butter: place 12 tablespoons unsalted butter in a small saucepan over medium-low heat. Swirl or stir occasionally and watch closely; the butter will foam, then the foam will subside and the butter will turn golden brown and smell nutty. Skim any foam from the surface, remove the pan from the heat, and pour the butter into a heatproof bowl, leaving any browned sediment in the pan. Let the butter cool until warm (not hot) before using.
- In the bowl of a stand mixer, combine the cooled browned butter with 1 cup packed brown sugar and 1/2 cup granulated sugar. Mix until the sugars are incorporated.
- Add 2 large eggs and 2 teaspoons vanilla extract to the mixer and beat until the mixture is smooth and uniform.
- With the mixer on low, slowly add the dry ingredients from step 2 and mix just until combined. Do not overmix.
- Stir in 2 cups semi-sweet chocolate chips and 3/4 cup chopped hazelnuts (skins removed) until evenly distributed.
- Spread the dough evenly into the prepared 9×13-inch pan, smoothing the top with a spatula. Sprinkle the top very lightly with sea salt.
- Bake for 25–30 minutes, or until the top is light golden brown and the edges begin to pull away from the pan.
- Cool the bars in the pan on a wire rack to room temperature. Once cooled, cut into squares and serve.
Reasons to Love Brown Butter Chocolate Chip Hazelnut Cookie Bars
These bars hit several sweet-spot criteria at once: deep flavor, easy preparation, and great texture. The brown butter transforms the whole cookie profile—it’s like caramel and toasted nuts wrapped into the fat—so you get more complex flavor with only one extra step.
No scooping required. Pressing the dough into a 9×13 pan is fast and forgiving. The bars are sturdy enough to pack in lunchboxes or share on a picnic, yet soft enough to be comforting with a cup of coffee.
Hazelnuts pair beautifully with brown butter and chocolate; they reinforce that toasty character without competing with the chocolate chips. A light sprinkle of sea salt on top lifts the flavors and gives the finished bars a bakery-style finish.
Texture-Safe Substitutions
If you need to swap ingredients, choose options that preserve moisture and structure. Here are sensible swaps that won’t ruin the chew or crumble.
- Butter: If you must use salted butter, reduce additional salt elsewhere. Unsalted controls final seasoning best, but salted will still brown and add flavor.
- Sugar: Swapping part of the brown sugar for more granulated sugar will make bars slightly less moist. Avoid replacing all brown sugar because it contributes chew and caramel notes.
- Chocolate chips: Use dark chocolate chips or chunks for deeper chocolate intensity, or milk chocolate for a sweeter bar. Bittersweet will be drier and less sweet but still fine.
- Hazelnuts: If hazelnuts are unavailable, toasted chopped almonds or pecans work texturally, though the flavor shifts. Chop uniformly for even distribution.
Essential Tools for Success
These few tools make the process smoother and protect the texture you’re after:
- Light-colored saucepan — helps you see the butter’s color change clearly when browning.
- Heatproof bowl — to stop the cooking immediately when you transfer the browned butter.
- Stand mixer or hand mixer — for thorough sugar-creamer without overheating; but mixing by hand works if you’re careful.
- 9×13-inch pan — size matters; a smaller or larger pan will change bake time and thickness.
- Wire rack — crucial for cooling to avoid trapped steam that makes the bottom soggy.
Avoid These Mistakes
Watch these common slip-ups so your bars come out as intended:
- Overbrowning the butter: Pull it off the heat once the foam subsides and tiny brown bits appear—but before it smokes. Butter can go from perfect to burnt quickly.
- Using hot butter: Let browned butter cool until warm. Hot butter will cook the eggs when mixed and can create a greasy, separated batter.
- Overmixing the dough: Once you add the flour, mix only until combined. Overworking develops gluten and yields a tougher bar.
- Incorrect pan size: A different pan changes thickness and bake time. Use a 9×13-inch pan for the texture in the recipe.
- Cutting too soon: Wait until fully cooled. Warm bars can crumble and won’t slice cleanly.
Spring–Summer–Fall–Winter Ideas
These bars are versatile across seasons. Small tweaks adapt them beautifully to the time of year:
- Spring: Add a handful of toasted, finely grated lemon zest to the batter for a bright note that pairs surprisingly well with the brown butter.
- Summer: Serve squares chilled with a scoop of vanilla ice cream for a quick dessert. The chilled chocolate is lovely in warm weather.
- Fall: Stir in a teaspoon of ground cinnamon or replace half the vanilla with maple extract for cozy autumnal warmth.
- Winter: Sprinkle a bit more sea salt and top with chopped candied orange peel for a festive contrast to the brown butter and chocolate.
Behind-the-Scenes Notes
I always brown butter in a light saucepan and swirl it rather than stir aggressively. Swirling promotes even browning. The sediment left in the pan is what gives the butter its deep flavor; you intentionally leave it behind when you pour, so the solids don’t overcook and become bitter. But a little of that flavor is what you want, which is why you pour off before scraping the fond.
Toast hazelnuts briefly in a dry skillet or in a 350°F oven for 8–10 minutes until their skins loosen. Rub them with a towel to remove most skins; this reduces bitterness and improves texture. Chop to medium-fine pieces so each bite has some nut but not big chunks that make cutting difficult.
Freezer-Friendly Notes
These bars freeze well, either whole or in portions. Cool completely, then wrap tightly in plastic wrap and place in a freezer-safe container or bag. They’ll keep for up to 3 months.
To serve, thaw in the refrigerator for a few hours or at room temperature for about 30–60 minutes. If you like them warm, reheat individual squares in a microwave for 10–15 seconds or warm in a 300°F oven for 7–10 minutes.
Reader Questions
Can I use pre-toasted hazelnuts?
Yes. If they’re already toasted and skins removed, use them as-is and chop to the size you prefer. Adjust roasting time if they already have color to avoid extra bitter notes.
What if I don’t have a stand mixer?
A hand mixer or even a sturdy wooden spoon will work. Cream the cooled browned butter with the sugars thoroughly, then beat in eggs and vanilla until smooth. Finish by folding in dry ingredients with a spatula to avoid overmixing.
Why is my butter grainy after browning?
Sometimes the milk solids clump when you pour warmed browned butter into a bowl. If it’s just texture and not burnt, it’s fine—those solids contribute flavor. Let the butter cool to warm before combining with sugars so it incorporates smoothly.
The Last Word
These Brown Butter Chocolate Chip Hazelnut Cookie Bars are straightforward to make and deliver bakery-level flavor with minimal fuss. The brown butter step asks for some attention, but it’s worth the few extra minutes for the depth it brings. Keep a small jar of these on hand for weekend guests, potlucks, or an easy gift—cut into squares, stack in parchment-lined boxes, and sprinkle a tiny pinch of sea salt just before wrapping.
Make a batch with confidence: follow the measures, mind the butter, and cool fully before slicing. You’ll have buttery, chocolate-studded bars with a toasty hazelnut crunch that disappear fast.
Brown Butter Chocolate Chip Hazelnut Cookie Bars
Ingredients
Ingredients
- 2 1/8 cupsall-purpose flour
- 1/2 teaspoonsea salt
- 1/2 teaspoonbaking soda
- 12 tablespoonsunsalted butter
- 1 cuppacked brown sugar
- 1/2 cupgranulated sugar
- 2 large eggs
- 2 teaspoonsvanilla extract
- 2 cupssemi-sweet chocolate chips
- 3/4 cupchopped hazelnutsskins removed
- Sea saltfor sprinkling over cookie bars
Instructions
Instructions
- Preheat the oven to 325°F. Spray a 9x13-inch baking pan with nonstick cooking spray and set aside.
- In a medium bowl, whisk together 2 1/8 cups all-purpose flour, 1/2 teaspoon sea salt, and 1/2 teaspoon baking soda. Set aside.
- Brown the butter: place 12 tablespoons unsalted butter in a small saucepan over medium-low heat. Swirl or stir occasionally and watch closely; the butter will foam, then the foam will subside and the butter will turn golden brown and smell nutty. Skim any foam from the surface, remove the pan from the heat, and pour the butter into a heatproof bowl, leaving any browned sediment in the pan. Let the butter cool until warm (not hot) before using.
- In the bowl of a stand mixer, combine the cooled browned butter with 1 cup packed brown sugar and 1/2 cup granulated sugar. Mix until the sugars are incorporated.
- Add 2 large eggs and 2 teaspoons vanilla extract to the mixer and beat until the mixture is smooth and uniform.
- With the mixer on low, slowly add the dry ingredients from step 2 and mix just until combined. Do not overmix.
- Stir in 2 cups semi-sweet chocolate chips and 3/4 cup chopped hazelnuts (skins removed) until evenly distributed.
- Spread the dough evenly into the prepared 9x13-inch pan, smoothing the top with a spatula. Sprinkle the top very lightly with sea salt.
- Bake for 25–30 minutes, or until the top is light golden brown and the edges begin to pull away from the pan.
- Cool the bars in the pan on a wire rack to room temperature. Once cooled, cut into squares and serve.
Equipment
- 9x13-inch baking pan
- nonstick cooking spray
- Mixing Bowl
- Saucepan
- Stand mixer
- Spatula
- Wire Rack
