Preparing the chocolate sponge cake
* Peheat oven to 350 F (175 C). Take a 10 inch-diameter (25 cm) oven pan with removable ring. Line it with parchment paper.
* Sprinkle it with cocoa powder.
* Place the hazelnuts in an oven pan and roast them for 10 – 15 minutes, until they begin losing their skin. Remove the skins by placing the nuts in a kitchen cloth and rubbing the pieces together.
* Place the chocolate in a small saucepan and melt it at bain-marie on a larger container filled with boiling water, stirring frequently.
* Put the hazelnuts in a food processor with 4 oz (115 gr) of the sugar. Run the blade until the nuts are reduced to a very fine powder.
* Remove the mixture from the food processor and transfer it to a small bowl. Work into it the butter with your hands for about 2 – 3 minutes to soften it.
* Combine the hazelnuts, the softened butter, and the melted chocolate, and mix it thoroughly until smooth.
* Combine the egg yolks one at a time with the hazelnut-chocolate mixture, reserving the egg whites.
* Sift in the flour, mixing continuously.
* Beat the egg whites. When they are half beaten add the remaining 4 oz (115 gr) of sugar and beat the mixture until peaks are formed.
* Combine the egg whites to the hazelnut-chocolate mixture in several times, stirring gently with a top–to–bottom movement.
* Pour the mixture in the oven pan level with a spatula and bake it for approximately 30–40 minutes.
* Remove from the oven and let the cake cool at room temperature
Preparing the filling
* Put the cream in a saucepan and turn the heat to medium. * Remove the pan from the heat immediately before the cream starts boiling.
* Add the diced chocolate, and stir until dissolved.
* In a small bowl, using a spatula or a fork, beat the butter until soft.
* Stir the butter into the cream and let it cool at room temperature for about 2 hours.
Assembling the cake
* Remove the cake from the pan and turn it upside down, so that the bottom smooth face is now the top. Don’t forget to peel the paper off.
* Cut the cake into 2 layers. Use toothpicks as a guide.
* Brush the bottom layer with the rum, and spread half of the filling over it.
* Place the other layer on top . .. . . brush it with rum. . .. . . and spread the rest of the filling on the top and sides of the cake. Place the cake in the refrigerator.
* Put the cream in a saucepan and turn the heat to medium. * Remove from the heat immediately before the cream starts boiling. Add the diced chocolate, and stir until dissolved.
* Whisk and beat the glaze until it is very light and soft.
* Remove the cake from the refrigerator, cover it with the glaze, and spread it uniformly with a spatula. Put the cake back in the refrigerator for 15 – 20 minutes to allow the glaze to cool. Keep in the refrigerator until serving time. Decorate the sides with crushed hazelnuts.
for the chocolate sponge cake
* 1 - 1/2 cups (180 gr) hazelnuts
* 7 oz (200 gr) semi-sweet chocolate, finely diced
* 4 + 4 oz (115 + 115 gr) sugar
* 1 + 6 oz (30 + 170 gr) butter, at room temperature
* 8 eggs, separated
* 3/4 cup (110 gr) flour
for the chocolate filling
* 1 cup (250 cc) heavy cream
* 12 oz (340 gr) semi–sweet chocolate, diced
* 2 oz (60 gr) butter, at room temperature
for the finishing and the glaze
* 1/4 cup (60 cc) rum or brandy
*3/4 cup (180 cc) heavy cream
* 6 oz (180 gr ) semi–sweet chocolate, diced