Preheat oven to 375 degrees F (190 C). Prepare a 9 or 10-inch springform pan with parchment paper liner on the bottom, grease sides with butter.
Allow all ingredients to come to room temperature. Separate eggs, making sure that no yolk is present in the separated egg whites.
In a large, heatproof bowl, combine chocolate and unsalted butter. Set the bowl on top of a medium saucepan with about 2 inches of barely simmering water. Allow chocolate and butter to melt completely, stirring often. Remove from heat and allow to cool slightly.
Meanwhile, in bowl of food processor, grind hazelnuts with flour until well combined.
In separate medium bowl, whisk together egg yolks 1/2 cup of the sugar, the 1/3 cup of brown sugar, the hazelnut liqueur, and the vanilla. Whisk until mixture is thick and pale golden in color. Whisk egg mixture into chocolate mixture and continue whisking until smooth.
In a separate large bowl or in the bowl of electric mixer, beat egg whites and cream of tartar on medium speed until soft peaks form. Gradually add in remaining 1/4 cup sugar, while continuing to beat on high speed. Beat until the peaks are stiff and glossy, but not dry.
Using a rubber spatula, fold in 1/4 of the egg white mixture into the chocolate mixture. Now fold in the nut and flour mixture. Finally, gently fold in the remaining egg whites. Pour batter into prepared springform pan and smooth top to even out. Bake for 35 to 40 minutes, or until a toothpick inserted 1-inch from the edge of the pan, comes out clean (center will remain moist and gooey). Let cool completely in the pan on a rack; the center will sink as it cools. Slide a thin knife around the edge of the torte to loosen, then remove sides. To obtain a smooth finish for icing, invert torte onto serving plate and glaze upside down. Or simply leave right side up and dust with confectioners' sugar. Serve with sweetened whipped cream or chocolate ganache.
Makes 10-12 servings.
3/4 Cup Heavy Cream
8 Ounces Semisweet or Bittersweet Chocolate, finely chopped
In small saucepan, bring cream to a boil. Remove from heat and add in chocolate. Stir until most of the chocolate has melted. Cover and let stand for 10 minutes. Stir or whisk very gently until smooth. Add in 1 tablespoon of flavored liqueur of choice.
To glaze cake, use a ladle and pour a small amount in middle. Use an offset spatula to move ganache from middle to sides. Add more as needed. Ladle around edge and allow to drizzle off. For a smoother look, finish with spatula.
Date: May 25, 2002