Ingredients
- Sponge Cake:
- 4 eggs separated
- 3/4 cup granulated sugar
- Pinch of salt
- 1/2 cup all-purpose flour
- 1/2 cup cornstarch
- Filling and Garnish:
- 1/2 cup hazelnuts
- 10 ounces semisweet chocolate finely choppe
- 2 cups heavy cream
- 1/4 cup granulated sugar
- 3 tablespoons whole or amber rum plus more for brushing 2 teaspoons confectioners sugar
- 1 teaspoon unsweetened cocoa powder
Preparation
Step 1
Sponge Cake:
Preheat oven to 350 degrees. Butter a 10x2” round cake pan and line bottom with parchment paper. In large bowl using an electric mixer, lightly beat egg yolks. Beat in 6 tablespoons granulated sugar in a stream. Beat mixture at high speed until it has tripled in volume and forms a thick ribbon when beaters are lifted. In medium bowl beat egg whites with the salt until very soft peaks form. Beat in remaining 6 tablespoons sugar in a stream and beat on high speed until firm peaks form. Using a spatula, fold beaten whites into egg yolk mixture. Stir flour and cornstarch together and sift over the batter in 3 or 4 additions folding gently with a rubber spatula until blended. Pour batter into prepared pan and bake for 30 minutes, until sponge cake has risen well and is firm in the center. Leave oven on. Loosen cake and invert on a rack. Turn the cake right-side up and let cool completely.
Filling and Garnish:
Spread hazelnuts on a baking sheet and toast in oven for 15-20 minutes until the skins blister. Transfer hazelnuts to a kitchen towel and cool slightly, then rub them together to loosen the skins. Coarsely chop nuts and place in a bowl. When nuts have cooled completely, stir in 2 ounces chopped chocolate. In heavy saucepan bring 1-1/4 cups cream to a boil over moderately high heat. Remove from heat and add remaining 8 ounces chopped chocolate. Let stand for 5 minutes, then whisk until smooth. Pour mixture into medium bowl and let cool to room temperature, then refrigerate until cold and set. In bowl combine remaining 3/4 cup cream with granulated sugar and beat until still. Cover and refrigerate. Butter a 1-1/2 quart glass bowl and line with plastic wrap, pressing the wrap smoothly against the inside of the bowl. Cut a 1/4” horizontal slice from the top of the sponge cake and set aside, covered. Cut 10 1/4” wide vertical slices from the sponge cake. Use these slices to line prepared bowl, fitting them tightly against each other, without overlapping, to completely line bowl. Reserve remaining sponge cake for another use. Sprinkle sponge cake in mold with 2 tablespoons rum. Beat the chilled chocolate filling on medium speed until light. Spread filling over sponge cake in bowl in an even 1/2” layer. Remove whipped cream from refrigerator and rewhip until firm, then beat in remaining 1 tablespoon rum. Fold chopped hazelnuts and chocolate and spoon filling into mold. Smooth surface. Trim sponge cake slices flush with filling. Cover with reserved cake layer and trim it to fit neatly inside the bowl. Cover with plastic wrap and freeze for 4-5 hours to set fillings, then refrigerate until serving time. To unmold, invert bowl onto a platter and lift off the bowl.