Preheat the oven to 350F. Using an electric mixer, beat the egg whites, gradually adding the sugar, until firm. Fold in the ground almonds, hazelnuts and the flour. On an oiled baking sheet, form three disks, about 3/8 inch thick. Bake for about 20 minutes. Remove the disks quickly from the sheet and cool. Stack the disks and trim them so they are the same size. Chop the bitter chocolate and place in a bowl, fitted into a pan containing 1-inch simmering water. Whip the cream with the electric beater and divide in two. Add a 1/2 cup sieved confectioner╒s sugar to half the egg whites, whip and put aside. Add the rest of the confectioner╒s sugar to the remaining egg whites and the melted bitter chocolate. Cover alternate layers of cake with chocolate mixture and white mixture, covering the outside of the cake with the chocolate mixture. Shave the rest of the chocolate and decorate the cake with it. Refrigerate until serving time.
