Quick Recipe Version (TL;DR)

Yield: 12 servings (one tall 3-layer 8-inch cake)
Prep Time: 1 hour 15 minutes
Cook Time: 35 minutes
Total Time: 3 hours (including cooling and chilling)

Quick Ingredients

For the cake: 1 cup finely ground toasted hazelnuts; 2 cups all-purpose flour; 2 cups granulated sugar; 3/4 cup unsweetened cocoa powder; 2 tsp baking powder; 1 1/2 tsp baking soda; 1 tsp fine salt; 3 large eggs; 1 1/2 cups buttermilk; 1/2 cup neutral oil; 1 cup hot strong coffee (or hot water); 2 tsp vanilla.
For the buttercream: 1 1/2 cups unsalted butter; 4 cups confectioners’ sugar; 1/2 cup unsweetened cocoa powder; 1/2 cup chocolate-hazelnut spread; 1/2 cup very finely ground toasted hazelnuts; 1/4–1/3 cup heavy cream; 2 tsp vanilla; pinch salt.
For the ganache: 18 oz (510 g) bittersweet chocolate, finely chopped; 1 1/2 cups heavy cream; 2 Tbsp unsalted butter; 1 Tbsp honey or corn syrup (optional, for shine).
For garnish: 1 cup whole toasted hazelnuts; a handful of chopped hazelnuts; 8–12 chocolate hazelnut truffles.

Do This

1. Toast hazelnuts at 350°F (175°C) until fragrant (8–10 minutes), rub off skins, cool, then grind: 1 cup finely for cake, 1/2 cup very finely for buttercream, reserve remaining whole/chopped for garnish.
2. Line three 8-inch round pans; whisk dry cake ingredients (including ground hazelnuts), then beat in eggs, buttermilk, oil, vanilla, and finally hot coffee until smooth.
3. Divide batter between pans and bake at 350°F (175°C) for 22–26 minutes; cool completely.
4. Beat butter, cocoa, and chocolate-hazelnut spread; gradually add confectioners’ sugar, ground hazelnuts, cream, vanilla, and salt until fluffy.
5. For ganache, pour hot cream over chopped chocolate; let stand, add butter (and honey/corn syrup), then stir until glossy and cool until spreadable.
6. Fill layers with buttercream, crumb-coat the cake, chill, then frost with ganache; decorate top with whole hazelnuts, chopped hazelnuts around the base, and chocolate hazelnut truffles.

Why You’ll Love This Recipe

Deep, layered chocolate and hazelnut flavors in every bite: in the cake, the buttercream, and the ganache.
A tall, elegant, European-style celebration cake that looks bakery-quality but is completely doable at home.
Toasted hazelnuts add incredible aroma, crunch, and sophistication to a classic chocolate layer cake.
Perfect for birthdays, holidays, or any special occasion where you want a showstopper centerpiece.

Grocery List

Produce: None.
Dairy: Unsalted butter, buttermilk, heavy cream, eggs.
Pantry: Whole hazelnuts, all-purpose flour, granulated sugar, confectioners’ sugar, unsweetened cocoa powder, bittersweet chocolate, chocolate-hazelnut spread, neutral oil, vanilla extract, honey or light corn syrup (optional), baking powder, baking soda, fine sea salt, coffee (or instant coffee + water), chocolate hazelnut truffles.

Full Ingredients

For the Toasted Hazelnuts

2 1/2 cups (about 340 g) whole hazelnuts, preferably blanched, divided:
- 1 cup (120 g) finely ground for the cake batter
- 1/2 cup (60 g) very finely ground for the buttercream
- About 1 cup (120 g) left whole or roughly chopped for garnish

For the Chocolate Hazelnut Cake Layers

1 cup (120 g) finely ground toasted hazelnuts (from above), lightly packed
2 cups (260 g) all-purpose flour, spooned and leveled
2 cups (400 g) granulated sugar
3/4 cup (65 g) unsweetened cocoa powder (Dutch-process preferred for deeper flavor)
2 tsp baking powder
1 1/2 tsp baking soda
1 tsp fine sea salt
3 large eggs, at room temperature
1 1/2 cups (360 ml) buttermilk, at room temperature
1/2 cup (120 ml) neutral oil (such as canola, sunflower, or grapeseed)
1 cup (240 ml) very hot strong coffee (or very hot water)
2 tsp pure vanilla extract

For the Chocolate Hazelnut Buttercream

1 1/2 cups (340 g) unsalted butter, very soft but not melted
4 cups (480 g) confectioners’ sugar, sifted
1/2 cup (45 g) unsweetened cocoa powder, sifted
1/2 cup (150 g) chocolate-hazelnut spread
1/2 cup (60 g) very finely ground toasted hazelnuts (from above)
1/4–1/3 cup (60–80 ml) heavy cream, as needed for consistency
2 tsp pure vanilla extract
1/4 tsp fine sea salt (or to taste)

For the Chocolate Ganache Frosting

18 oz (510 g) bittersweet or semisweet chocolate (60–70% cacao), finely chopped
1 1/2 cups (360 ml) heavy cream
2 Tbsp (28 g) unsalted butter, at room temperature
1 Tbsp (15 ml) honey or light corn syrup (optional, for extra shine and softness)

For Garnish and Assembly

Reserved whole toasted hazelnuts (about 1 cup / 120 g)
A small handful of toasted hazelnuts, finely chopped (for the base/sides)
8–12 chocolate hazelnut truffles (store-bought or homemade)
Extra cocoa powder or grated chocolate (optional, for dusting)

Step-by-Step Instructions

Step 1: Toast and Prepare the Hazelnuts

Preheat your oven to 350°F (175°C). Spread the hazelnuts in a single layer on a baking sheet. Toast for 8–10 minutes, shaking the pan once or twice, until they smell fragrant and the skins are darkened. Watch closely toward the end so they do not burn.

If your hazelnuts still have skins, wrap the warm nuts in a clean kitchen towel and rub them together to loosen and remove most of the skins. It is fine if some skins remain. Let the nuts cool completely.

Once cooled, place 1 cup (120 g) of the hazelnuts in a food processor with 2–3 tablespoons of the measured flour from the cake ingredients. Pulse until very finely ground, like coarse sand, but stop before they turn into paste. Set aside for the cake batter.

Place another 1/2 cup (60 g) hazelnuts in the processor and pulse until very finely ground, almost powdery. This batch is for the buttercream. Reserve the remaining 1 cup (about 120 g) hazelnuts whole for garnish; chop a small handful finely if you would like extra crunch around the base of the cake.

Step 2: Prepare the Pans and Preheat the Oven

Keep the oven at 350°F (175°C) if it has cooled. Grease three 8-inch (20 cm) round cake pans with butter or baking spray. Line the bottoms with rounds of parchment paper, then grease the parchment as well. Lightly dust the inside of each pan with cocoa powder or flour, tapping out any excess.

Having the pans ready before you mix the batter is important because the leavening starts working as soon as the wet and dry ingredients meet. Also, make sure your eggs and buttermilk are at room temperature so the batter mixes smoothly and bakes evenly.

Step 3: Make the Chocolate Hazelnut Cake Batter

In a large mixing bowl, whisk together the dry ingredients: 2 cups (260 g) flour (minus the few tablespoons you used with the nuts), 2 cups (400 g) sugar, 3/4 cup (65 g) cocoa powder, 2 tsp baking powder, 1 1/2 tsp baking soda, 1 tsp salt, and the 1 cup (120 g) finely ground hazelnuts. Make sure there are no cocoa or baking soda lumps.

In a separate bowl or large measuring jug, whisk the eggs until the yolks and whites are blended, then whisk in the buttermilk, oil, and vanilla. Pour this wet mixture into the dry ingredients and mix with a spatula or mixer on low speed just until combined; the batter will be thick at this point.

Gradually pour in the hot coffee (or hot water) while whisking on low. The batter will become quite thin and smooth—that is exactly how it should be. Scrape down the bowl to ensure everything is evenly mixed, but avoid over-beating.

Step 4: Bake and Cool the Cake Layers

Divide the batter evenly among the three prepared pans (a kitchen scale helps: aim for roughly the same weight in each pan). Smooth the tops gently with a spatula.

Bake at 350°F (175°C) for 22–26 minutes, rotating the pans halfway through if your oven bakes unevenly. The cakes are done when a toothpick inserted in the center comes out with a few moist crumbs but no wet batter, and the tops spring back lightly when touched.

Remove the pans to a wire rack and let the cakes cool in the pans for 10–15 minutes. Run a thin knife around the edges, then carefully turn each layer out onto the rack, peel off the parchment, and flip right side up. Allow the layers to cool completely (at least 1 hour) before frosting. For tidier assembly, you can wrap cooled layers in plastic and chill them for 30 minutes.

Step 5: Make the Chocolate Hazelnut Buttercream

In a large bowl, beat the softened butter on medium speed for 2–3 minutes until pale and creamy. Add the chocolate-hazelnut spread and beat again until smooth.

In a separate bowl, whisk together the confectioners’ sugar and cocoa powder to break up any lumps. With the mixer on low speed, gradually add this mixture to the butter, a cup at a time, mixing until incorporated before adding more. Scrape down the sides and bottom of the bowl as needed.

Add the 1/2 cup (60 g) very finely ground hazelnuts, vanilla, and salt. Beat on low to combine, then add 1/4 cup (60 ml) of heavy cream. Increase speed to medium-high and whip for 2–3 minutes, until the buttercream is fluffy and lighter in color. If it seems too stiff, add more cream 1 tablespoon at a time. If it is too soft, add a little more confectioners’ sugar. Set aside at cool room temperature while you prepare the ganache.

Step 6: Make the Chocolate Ganache Frosting

Place the finely chopped chocolate in a heatproof bowl. In a small saucepan, heat the cream over medium heat until it just begins to simmer around the edges; do not let it boil. Immediately pour the hot cream over the chocolate, making sure all the chocolate is submerged. Let it sit undisturbed for 2–3 minutes.

Add the butter and honey or corn syrup (if using). Starting in the center of the bowl, gently stir in small circles, slowly working outward, until the mixture becomes smooth, thick, and glossy. If there are any unmelted bits of chocolate, you can briefly warm the bowl over a pan of barely simmering water and stir again.

Let the ganache cool at room temperature, stirring occasionally, until it thickens to a spreadable consistency, similar to soft peanut butter. This usually takes 20–30 minutes. If it gets too firm, gently warm it in short bursts in the microwave or over a warm water bath, stirring often.

Step 7: Assemble and Fill the Cake

Place one cooled cake layer on a serving plate or cake stand. If the tops of the cakes are very domed, level them with a long serrated knife to create flat surfaces (save the crumbs for snacking or decorating).

Spread about 3/4 to 1 cup of the chocolate hazelnut buttercream evenly over the first layer, going right to the edges. Top with the second layer, pressing gently to secure, and repeat with another 3/4 to 1 cup buttercream. Place the third layer on top, bottom-side up for the flattest finish.

Use a thin layer of the remaining buttercream to lightly frost the sides and top of the cake—a “crumb coat” that traps any loose crumbs. Smooth it with an offset spatula or bench scraper. Chill the crumb-coated cake in the refrigerator for 20–30 minutes, until the buttercream is firm to the touch. This makes the ganache finish much easier and cleaner.

Step 8: Frost with Ganache and Decorate Elegantly

Once the crumb coat is firm and the ganache is spreadable, spoon some ganache onto the top of the cake and gently push it toward the edges, letting a little drip decoratively down the sides if you like. Use more ganache to cover the sides completely, smoothing with a spatula or leaving soft swoops for a rustic, European patisserie look.

While the ganache is still soft, press the finely chopped toasted hazelnuts around the base of the cake to form a neat border. Arrange whole toasted hazelnuts and chocolate hazelnut truffles on top in a circle or cluster—think of a crown around the edge or an elegant mound in the center. If desired, dust lightly with cocoa powder or add a sprinkle of grated chocolate.

Chill the decorated cake for at least 30 minutes to set the ganache before slicing. For the best texture and flavor, let the cake sit at cool room temperature for 20–30 minutes before serving so the buttercream and ganache soften slightly.

Pro Tips

Grind hazelnuts with flour: Always pulse nuts with a bit of flour to prevent them from turning into nut butter. Stop grinding as soon as the mixture looks like coarse sand.
Use room-temperature ingredients: Room-temperature eggs and buttermilk help the batter emulsify properly, giving you tender, even layers that rise well.
Do not overbake: Chocolate cakes dry out quickly. Pull the layers as soon as a toothpick comes out with a few moist crumbs rather than waiting for it to be completely clean.
Chill between steps: A chilled, crumb-coated cake plus slightly thickened ganache equals much smoother sides and fewer drips where you do not want them.
Slice with a hot knife: For clean, elegant slices that show off the layers, dip a long sharp knife in hot water, wipe it dry, and cut, wiping between slices as needed.

Variations

Mocha Hazelnut Layer Cake: Add 2–3 tsp instant espresso powder to the hot coffee before mixing the batter. You can also brush the cooled cake layers lightly with cooled espresso for extra coffee depth.
Raspberry Chocolate Hazelnut Cake: Spread a thin layer of good-quality raspberry jam over each cake layer before adding the buttercream. Garnish the top with fresh raspberries alongside the hazelnuts and truffles.
Two-Layer Version: Bake the batter in two 9-inch round pans instead of three 8-inch pans, increasing the baking time by a few minutes. You will have enough buttercream and ganache to generously frost the larger cake.

Storage & Make-Ahead

The fully assembled cake will keep, covered, in the refrigerator for up to 3 days. For the best texture, remove it from the fridge 30–45 minutes before serving so the buttercream and ganache soften.

You can bake the cake layers up to 2 days ahead. Once completely cool, wrap each layer tightly in plastic wrap and store at room temperature, or freeze for up to 2 months (thaw in the fridge overnight, then bring to room temperature before assembling).

The buttercream can be made 2–3 days ahead and refrigerated in an airtight container. Let it come to room temperature and re-whip briefly before using. Ganache is best made the day you plan to frost the cake; if it firms up too much, gently rewarm and stir until smooth.

Nutrition (per serving)

Approximate values for 1 of 12 slices: 820 calories; 56 g fat; 30 g saturated fat; 88 g carbohydrates; 5 g fiber; 66 g sugars; 9 g protein; 380 mg sodium. Actual values will vary based on specific ingredients and portion sizes.

Chocolate Hazelnut Layer Cake with Ganache and Truffles