These blondies are exactly what they sound like: a chewy, brown-butter–forward blondie wrapped around a thin, frozen layer of Nutella. The contrast between the toasty, caramelized butter flavor in the batter and the warm, chocolaty hazelnut center is what keeps people coming back for another square. They look impressive, but they’re straightforward to make if you follow the steps and give the Nutella its moment in the freezer.

I test desserts constantly for the blog, and this recipe hits the reliable bake trifecta — texture, flavor, and simplicity. The brown butter brings a nutty depth that plays beautifully with the hazelnuts and chocolate chunks folded into the batter. A light sprinkle of Maldon on top finishes each blondie with a pop that lifts the sweetness.

I’ll walk you through ingredient notes, a step-by-step method using the exact directions, tools that make the job easier, troubleshooting fixes, sensible swaps for health-conscious bakers, and quick answers to common questions. If you bake once with these instructions, you’ll know how to repeat them without surprises.

Ingredient Breakdown

Ingredients

1/2 cup (175g) Nutella — the molten, hazelnut-chocolate core; freeze it flat so it holds shape when you assemble.
3/4 cup (1 1/2 sticks/170g) unsalted butter, cut into chunks — browned for a nutty, caramel aroma; cutting into chunks helps it melt evenly.
1 1/4 cup (250g) packed light brown sugar — adds chew and a light molasses flavor; packed gives consistent sweetness and moisture.
2 large eggs — provide structure and lift; room temperature eggs emulsify better with brown butter.
1 large egg yolk — adds extra richness and tenderness.
2 teaspoons vanilla extract — brightens and rounds flavors; use pure vanilla if you have it.
1 teaspoon baking powder — gives a modest rise so the blondies are chewy but not cakey.
1/2 teaspoon kosher salt — balances sweetness; use measured kosher salt for consistency.
2 cups (250g) all-purpose flour — the structural base; measure accurately to avoid dry blondies.
1/2 cup (75g) semisweet chocolate chunks or chips — pockets of melty chocolate contrast the Nutella center.
1/2 cup (65g) coarsely chopped hazelnuts — add crunch and echo Nutella’s flavor; toast briefly if you want extra depth.
maldon flake sea salt, for topping — optional but recommended; the flakes give a clean, crisp finish and offset sweetness.

How to Prepare (Nutella-Stuffed Brown Butter Blondies)

Line an 8-by-8-inch square baking pan with parchment paper. Spread the 1/2 cup (175g) Nutella in a thin, even layer over the bottom of the pan. Freeze until the Nutella is solid, at least 20 minutes.
While the Nutella freezes, brown the butter: melt the 3/4 cup (1 1/2 sticks/170g) unsalted butter in a light-colored saucepan over medium heat. Swirl the pan occasionally. The butter will foam, then the foam will subside as the milk solids sink and begin to turn light golden brown. Remove from heat as soon as the solids are a light golden brown and the butter smells nutty. Watch closely to avoid burning.
Let the browned butter cool to lukewarm (so it is no longer hot to the touch).
Preheat the oven to 350°F (177°C). If you have a second 8-by-8-inch pan, line it with parchment and set it aside. If you only have one pan, keep the Nutella-lined pan in the freezer on the parchment; when the Nutella is solid you will remove the Nutella layer from that parchment and set the parchment with Nutella back in the freezer while you line the pan with a fresh piece of parchment.
In a large bowl or the bowl of a stand mixer fitted with the whisk attachment, combine 1 1/4 cups (250g) packed light brown sugar, 2 large eggs, 1 large egg yolk, 2 teaspoons vanilla extract, 1/2 teaspoon kosher salt, and 1 teaspoon baking powder. Beat on high speed for 2 to 3 minutes, until the mixture is lighter in color and thickened but not stiff.
Reduce the mixer to low and slowly drizzle in the lukewarm browned butter until fully incorporated.
Sprinkle the 2 cups (250g) all-purpose flour over the batter and mix on low speed until just incorporated. Scrape down the sides of the bowl as needed; do not overmix.
Fold in 1/2 cup (75g) semisweet chocolate chunks or chips and 1/2 cup (65g) coarsely chopped hazelnuts, reserving a spoonful of each for the top.
Spread half of the dough in an even layer in the prepared (clean) 8-by-8-inch pan.
Remove the frozen Nutella from the freezer. If it is still in its parchment, gently lift the Nutella layer and set it, Nutella-side down, on top of the dough in the pan. If you used two pans, lift the Nutella layer out of its pan and place it on the dough in the second pan. Press gently so the Nutella sits flat and even.
Spread the remaining dough in an even layer over the Nutella so it is fully covered. Sprinkle the reserved chocolate chunks and hazelnut pieces over the top, and finish with a light sprinkling of Maldon flake sea salt.
Bake on the center rack for 35 to 40 minutes, until the top is shiny and set and the edges are starting to brown. (Blondies may still be moist inside; use the appearance of the top and edges rather than a toothpick as your guide.)
Transfer the pan to a wire rack and let the blondies cool to room temperature.
Lift the entire block of blondies from the pan using the parchment paper. Using a large chef’s knife, cut into 16 even squares, wiping the knife clean between cuts for neat slices.
Store the blondies in an airtight container at room temperature for up to 3 days.

Top Reasons to Make (Nutella-Stuffed Brown Butter Blondies)

Flavor layering: Brown butter, hazelnuts, chocolate chunks, and Nutella combine for a multi-dimensional bite that feels gourmet but takes modest effort.
Impressive presentation: The clean squares with a glossy top and a few salty flakes read like something from a bake shop.
Make-ahead convenience: Freezing the Nutella layer first is a small step that pays off — you can assemble when busy and bake when guests arrive.
Great texture control: The recipe is forgiving; the top sets and the interior stays slightly moist, so you don’t need a toothpick to know when they’re done.
Everyone-friendly: No obscure ingredients, and most home bakers already have everything on hand or can pick it up in a single trip.

No-Store Runs Needed

One of the best parts of this recipe is that it’s built from kitchen basics: butter, sugar, eggs, flour, and chocolate. If you already have Nutella, you likely have most of the rest. The only specialty items that might require a quick store run are the Maldon flake sea salt and the hazelnuts if you don’t keep nuts on hand. If you don’t have Maldon, a light sprinkle of any flaky finishing salt will work. If you’re missing hazelnuts, pecans or walnuts make an acceptable substitute, but they’ll change the flavor profile slightly.

Essential Tools for Success

8-by-8-inch square baking pan — size matters here; using a different pan will change thickness and bake time.
Parchment paper — makes lifting the blondie block easy and helps you move the Nutella layer without a mess.
Light-colored saucepan for browning butter — a light pan lets you see the milk solids so you can stop before they burn.
Stand mixer with whisk attachment or a strong hand whisk — creaming the eggs and sugar gives volume; the mixer speeds things up.
Wire rack — for even cooling; letting them cool fully before slicing keeps edges neat.
Large chef’s knife — keep it clean between cuts for tidy squares.

Problems & Prevention

Soggy middle or runny Nutella

If the Nutella isn’t frozen solid before assembly, it will spread into the batter and cause a gooey interior that’s hard to slice. Freeze the Nutella layer at least 20 minutes and keep the parchment under it while you prepare the pan if you only have one pan. This ensures a clean layer that lifts and transfers easily.

Burnt browned butter

Browned butter goes from nutty to burnt very quickly. Use a light-colored pan and remove from heat as soon as the milk solids are light golden brown and fragrant. Don’t walk away; swirling the pan helps even browning.

Cakey blondies

Overmixing once the flour is added adds gluten and yields a cakeier texture. Mix on low and stop as soon as the flour disappears. Also, don’t overbake — look for a shiny, set top and slightly browned edges rather than relying on a toothpick.

Crumbly slices

Let the blondies cool completely to room temperature before lifting and slicing. Warm blondies will tear. Use a sharp, large chef’s knife and wipe it clean between cuts for tidy squares.

Health-Conscious Tweaks

These are indulgent bars, but you can make small swaps to adjust health profile without losing the core experience.

Reduce sugar slightly: You can try cutting brown sugar by 10–15% (so around 1 cup plus 2 tablespoons) and assess sweetness. Texture will remain chewy but slightly less sweet.
Whole-grain flour swap: Replace up to 25% of the all-purpose flour with whole wheat pastry flour for a nuttier flavor and slightly more fiber. Keep an eye on texture — don’t go beyond 25% without adjustments.
Nut substitute: If nut allergies are a concern, omit the hazelnuts and still use Nutella only if it’s safe. For a nut-free version, use a chocolate-hazelnut-free spread you trust, though the original flavor profile will change.
Portion control: Cut into 25 smaller squares instead of 16 to reduce portion size while still satisfying a sweet craving.

Author’s Commentary

I developed this version because I wanted a blondie that felt adult and layered, not just extra-sweet. Brown butter changes everything. It’s a small technique that gives baked goods a toasty, caramelized backbone, and it’s worth the few extra minutes at the stove. I also like the tactile moment of lifting a frozen Nutella sheet and placing it between dough layers — it’s oddly satisfying and guarantees a centered filling.

I recommend making these for a dinner party or holiday tray. They travel well for a day and look like you spent far more time than you did. If you’re baking for kids, skip the Maldon on top but keep the chopped hazelnuts inside — they add texture without being mandatory.

Leftovers & Meal Prep

Store at room temperature in an airtight container for up to three days. If you want them a little melty, microwave a single square for 8–12 seconds to soften the Nutella center. For longer storage, freeze the cut squares in a single layer on a baking sheet, then transfer to a freezer-safe bag for up to 1 month. Thaw at room temperature or gently reheat in a low oven.

Ready, Set, Cook

Preheat the oven, line the pan, and get the Nutella in the freezer first. Brown the butter while the Nutella firms up, then mix the batter and assemble as directed. The process is sequential and tidy: freezing, browning, mixing, assembling, and baking. Allow time to cool fully before slicing for clean edges. These blondies reward patience — the flavors deepen as they sit a few hours, so if you can wait, they’ll taste even better the next day.

If you try them, I’d love to hear how they turned out — whether you kept things classic or made a swap. Happy baking, and don’t forget the Maldon.