Lightly coat the insides of two 9-by-1 1/2 inch round cake pans with melted butter. Line each pan with parchment paper, then lightly coat the parchment paper with more melted butter. Set aside.
Heat oven to 325 degrees F.
Heat 1 inch of water in bottom of double boiler over medium heat. Place the remaining butter and 6 1/2 ounces of semisweet chocolate in top half of double boiler. Tightly cover the top with film wrap. Allow to heat for 10 to 12 minutes. Remove from heat, stir until smooth and hold at room temperature.
Place 2/3 cup egg yolks and 1 cup sugar in a bowl of an electric mixer fitted with paddle. Beat on high until lemon colored and slightly thickened, about 4 minutes. Scrape down sides of bowl and beat for additional 2 minutes.
While egg yolks are beating, whisk 2/3 cup egg whites ina large stainless-steel bowl until soft peaks form, about 3 minutes.
Using a rubber spatula, fold the melted chocolate mixture into the beaten egg yolk mixture. Add a quarter of the beaten egg whites, and stir to incorporate, then gently fold in remaining egg whites.
Divide between the prepared pans, spreading evenly and bake until a toothpick inserted in the center comes out clean, about 30 minutes. Remove the cakes from the oven and allow to cool in pans for 15 minutes. During baking the surface of the cake will form a crust; this crust will normally collapse when the cake is removed from the oven. Adjust the oven temperature to 450 degrees. Invert cakes onto cake plates. Remove parchment paper and refrigerate the cakes for 1 hour.
While cakes are cooling, prepare the ganache. First toast the hazelnuts on a baking sheet for 5 minutes in the 450-degree oven. Remove from the oven, and immediately cover with a damp towel. Invert another baking sheet over the top to steam the skins off. After 5 minutes, remove the skins from the nuts. Allow the nuts to cool to room temperature. In a food processor fitted with metal blade, chop nuts into 1/8-inch pieces.
Heat 1 1/2 cups heavy cream, 4 tablespoons butter and 1/4 cup sugar in a 2 1/2 quart saucepan over medium-high heat. Bring to a boil. Place 10 1/2 ounces semisweet chocolate pieces ina stainless-steel bowl. Pour the boiling cream over the chocolate, and allow to stand for 3 to 4 minutes. Stir until smooth.
Remove 1/2 cup chocolate ganache, and combine with chopped hazelnuts. Hold this mixture at room temperature to use for the filling. Remove another 1/2 cup chocolate ganache and reserve under refrigeration for 1 hour (this 1/2 cup will be used to decorate the Temptation) Hold the remaining chocolate ganache at room temperature until needed.
Puree the raspberries and 1/2 cup sugar in a food processor fitted with a steel blade for 12 to 15 seconds. Transfer to a stainless-steel bowl. Cover and refrigerate until needed.
Assemble and decorate the cake. Remove the cakes from the refrigerator. Using a cake spatula, spread 1/4 cup raspberry puree over the one cake. Spread the puree evenly to the edges. Spread the ganache and hazelnut mixture over the raspberry puree. Spread the ganache evenly to the edges. Invert the other cake layer on top of the ganache covered cake. Press the cakes together. Using a very sharp serrated knife, trim the top and sides of the cake so they are even. At this point, the cake must be refrigerated for 30 minutes.
Remove the well chilled cake from the refrigerator. Pour the room temperature chocolate ganache over the cake, spreading the with a spatula to create and even coating of ganache on the top and sides of the cake. Refrigerate the cake for 20 to 25 minutes to set the ganache.
Transfer the 1/2 cup well chilled ganache to a pastry bag fitted with a No. 2 star tip. Remove the cake from the refrigerator. Pipe eight to 12 stars on the top of the cake.
Using a vegetable peeler, shave chocolate curls from the 1 ounce piece of chocolate directly onto the center of the cake. Refrigerate the cake for 1 hour before slicing.
Temper the cake slices at room temperature for 1 1/2 to 2 hours before serving. Portion 1/4 cup raspberry puree onto each plate. Place a slice of cake in the center of each plate and serve.