Ingredients
Scale
Chocolate Cake
- 2 cups (240 g) all-purpose flour
- 1 3/4 cups (350 g) granulated sugar
- 3/4 cup (64 g) unsweetened cocoa powder
- 2 teaspoons baking soda
- 1 teaspoon baking powder
- 1/2 teaspoon fine salt
- 2 large eggs, room temperature
- 1 cup (240 ml) buttermilk, room temperature
- 1/2 cup (120 ml) neutral vegetable oil
- 2 teaspoons vanilla extract
- 1 cup (240 ml) hot freshly brewed coffee
Chocolate-Hazelnut Buttercream
- 1 1/2 cups (340 g) unsalted butter, softened
- 1 cup (about 300 g) chocolate-hazelnut spread
- 4 cups (480 g) powdered sugar
- 1/2 cup (43 g) unsweetened cocoa powder
- 1/3–1/2 cup (80–120 ml) heavy cream
- 1 teaspoon vanilla extract
- Pinch of fine salt
Chocolate Ganache
- 8 oz (227 g) semisweet chocolate, finely chopped
- 3/4 cup (180 ml) heavy cream
Decoration
- Chocolate-hazelnut truffles
- Chocolate-covered wafer pieces
- Chocolate bar pieces
- Whole toasted hazelnuts
- Chopped toasted hazelnuts
- Chocolate curls or crisp chocolate sprinkles
Instructions
- Preheat the oven to 350°F (175°C). Grease three 8-inch round cake pans. Line the bottoms with parchment paper and lightly grease the parchment.
- In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt. Break up any visible cocoa lumps.
- In a separate bowl, whisk the eggs, buttermilk, oil, and vanilla. Add the wet ingredients to the dry mixture and stir until just combined.
- Gradually pour in the hot coffee while mixing on low speed or whisking gently. The batter will be thin. This is expected. Do not add extra flour.
- Divide the batter evenly among the three pans. Bake for 25–30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs and no wet batter.
- Cool in the pans for about 10 minutes. Turn onto cooling racks, remove the parchment, and cool completely before assembling.
- For the frosting, beat softened butter for 2–3 minutes until fluffy. Beat in the chocolate-hazelnut spread. Gradually add powdered sugar and cocoa. Add vanilla and salt. Beat in heavy cream a little at a time until the frosting is thick, smooth, and spreadable.
- Level the cooled cakes if necessary. Place the first layer on a serving plate or cake board. Cover with an even layer of frosting. Repeat with the second layer, then add the third layer.
- Apply a thin crumb coat over the cake. Refrigerate for 15–20 minutes. Cover with the remaining frosting and smooth the top and sides. Chill for another 20–30 minutes.
- For the ganache, place finely chopped chocolate in a heatproof bowl. Heat the cream until steaming but not vigorously boiling. Pour it over the chocolate and leave undisturbed for 2 minutes. Stir slowly until smooth and glossy.
- Allow the ganache to cool and thicken slightly. Test one drip on the chilled cake. If it runs to the bottom immediately, let the ganache cool longer.
- Spoon ganache around the top edge to create drips of different lengths. Spread a thin amount across the top.
- Pipe generous chocolate-hazelnut frosting swirls over the top. Decorate with truffles, wafer pieces, chocolate pieces, toasted hazelnuts, chopped hazelnuts, and chocolate curls.
- For cleaner slices, chill briefly before cutting. Use a sharp knife warmed in hot water and wiped dry between cuts.
Notes
- Do not thicken the cake batter with extra flour. A fluid batter is expected after adding the coffee.
- All three cake layers must be completely cool before frosting.
- Room-temperature eggs and buttermilk mix more evenly into the batter.
- The frosting should be firm enough to support three layers. Add heavy cream gradually.
- Chill the frosted cake before adding ganache.
- Always make one test drip before covering the cake edge.
- For the crunchy texture shown in the finished cake, rely on toasted hazelnuts, crisp wafers, truffles, and chocolate pieces, rather than overbaking the cake to create a hard crust.
- Add wafer decorations closer to serving when possible so they remain crisp.
- Exact baking time varies by oven and pan material.
- The cake contains wheat/gluten, dairy, eggs, and tree nuts. Commercial chocolate spreads, wafers, truffles, and chocolate should also be checked for their own allergen statements.
- Prep Time: 45 minutes
- Additional/Chill Time: 1 hour 30 minutes
- Cook Time: 25–30 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American