Espresso Hazelnut Mousse Cake

Serves 10-12 | Prep Time: 2 hours | Chill Time: 4+ hours

A sophisticated dessert featuring layers of moist espresso sponge cake and silky hazelnut mousse, topped with a glossy chocolate ganache.

Ingredients

For the Espresso Sponge Cake:

  • 6 large eggs, separated
  • 3/4 cup (150g) granulated sugar, divided
  • 1/2 cup (60g) all-purpose flour
  • 1/4 cup (25g) unsweetened cocoa powder
  • 2 tablespoons instant espresso powder
  • 1/4 teaspoon salt
  • 2 tablespoons hot water

For the Hazelnut Mousse:

  • 1 cup (240ml) heavy cream
  • 3/4 cup (200g) Nutella or hazelnut spread
  • 8 oz (225g) cream cheese, softened
  • 1/2 cup (60g) powdered sugar
  • 1 packet (2.25 tsp) unflavored gelatin
  • 3 tablespoons cold water
  • 1/2 cup (60g) toasted hazelnuts, finely chopped

For the Chocolate Ganache:

  • 1/2 cup (120ml) heavy cream
  • 4 oz (115g) dark chocolate, finely chopped
  • 1 tablespoon butter
  • 1 tablespoon corn syrup (optional, for extra shine)

For Assembly:

  • 1/4 cup strong espresso or coffee, cooled
  • 2 tablespoons coffee liqueur (optional)
  • Whole toasted hazelnuts for decoration

Equipment Needed

  • 9-inch springform pan
  • Electric mixer
  • Large mixing bowls
  • Fine-mesh sieve
  • Rubber spatula
  • Small saucepan

Instructions

Prepare the Espresso Sponge Cake:

  1. Preheat and Prep: Preheat oven to 350°F (175°C). Grease a 9-inch springform pan and line the bottom with parchment paper.
  2. Dissolve Espresso: In a small bowl, dissolve instant espresso powder in hot water. Set aside to cool.
  3. Whip Egg Whites: In a clean bowl, whip egg whites until soft peaks form. Gradually add 1/4 cup sugar and whip until stiff, glossy peaks form. Set aside.
  4. Make Batter: In another large bowl, whisk egg yolks with remaining 1/2 cup sugar until pale and thick. Stir in the cooled espresso mixture.
  5. Add Dry Ingredients: Sift together flour, cocoa powder, and salt. Gently fold into the egg yolk mixture in three additions.
  6. Fold in Whites: Carefully fold 1/3 of the whipped egg whites into the batter to lighten it, then gently fold in the remaining whites in two additions.
  7. Bake: Pour into prepared pan and bake for 25-30 minutes, until a toothpick inserted in center comes out clean. Cool completely in pan.

Make the Hazelnut Mousse:

  1. Bloom Gelatin: Sprinkle gelatin over cold water in a small bowl. Let sit for 5 minutes to bloom.
  2. Prepare Base: In a large bowl, beat softened cream cheese until smooth. Add Nutella and powdered sugar, beating until well combined.
  3. Dissolve Gelatin: Microwave bloomed gelatin for 15-20 seconds until dissolved. Let cool slightly, then whisk into the Nutella mixture.
  4. Whip Cream: In a separate bowl, whip heavy cream to soft peaks. Fold 1/3 of the whipped cream into the Nutella mixture to lighten it, then gently fold in remaining cream.
  5. Add Nuts: Fold in chopped toasted hazelnuts.

Assemble the Cake:

  1. Prepare Pan: Clean the springform pan and line with plastic wrap, leaving overhang.
  2. Layer Cake: Cut the cooled sponge cake horizontally into 2 layers. Place one layer in the bottom of the prepared pan.
  3. Add Coffee Syrup: Combine cooled espresso and coffee liqueur (if using). Brush half over the cake layer.
  4. Add Mousse: Spread half the hazelnut mousse over the cake layer. Add the second cake layer and brush with remaining coffee mixture. Top with remaining mousse.
  5. Chill: Cover with plastic wrap and refrigerate for at least 4 hours or overnight.

Make the Chocolate Ganache:

  1. Heat Cream: In a small saucepan, heat heavy cream until just simmering.
  2. Make Ganache: Pour hot cream over chopped chocolate in a bowl. Let sit for 2 minutes, then stir from center outward until smooth. Stir in butter and corn syrup if using.
  3. Cool: Let ganache cool for 10-15 minutes until slightly thickened but still pourable.

Final Assembly:

  1. Unmold: Remove cake from springform pan using plastic wrap overhang. Place on serving plate.
  2. Glaze: Pour ganache over the top of the cake, letting it drip down the sides. Use an offset spatula to smooth if needed.
  3. Decorate: Arrange whole toasted hazelnuts around the top edge while ganache is still soft.
  4. Final Chill: Refrigerate for 30 minutes to set ganache before serving.

Serving and Storage

  • Serving: Use a sharp knife dipped in warm water and wiped clean between cuts for neat slices.
  • Storage: Keep refrigerated for up to 3 days. Remove from refrigerator 15 minutes before serving for best texture.
  • Make-Ahead: The cake can be assembled (without ganache) up to 2 days ahead. Add ganache on the day of serving.

Chef’s Tips

  • Toast Hazelnuts: Toast hazelnuts in a 350°F oven for 8-10 minutes until fragrant. Rub in a kitchen towel to remove skins.
  • Room Temperature Ingredients: Ensure cream cheese and eggs are at room temperature for the smoothest texture.
  • Gelatin Alternative: If you prefer, you can stabilize the mousse with an extra 1/4 cup of powdered sugar instead of gelatin, though it won’t be quite as firm.
  • Flavor Variations: Substitute almond butter and chopped almonds for a different nut flavor, or add a tablespoon of amaretto to the mousse.

This sophisticated dessert is perfect for special occasions and will impress any coffee and chocolate lover!