The following is a variation of a wonderful Viennese cake called a Rehrücken, or "saddle of venison" (so named because of the shape of the pan used to bake it in-not, fortunately, because of its flavor). Almonds make a good substitute for the hazelnuts.
Ingredients
Preparation
Step 1
Preheat oven to 350°F. and butter a 10-cup bundt pan or other tube pan.
Step 2
In a food processor pulse hazelnuts until finely ground.
Step 3
In a double boiler or a bowl set over a saucepan of barely simmering water melt chocolate, stirring until smooth. Remove top of double boiler or bowl from heat and cool chocolate slightly.
Step 4
In a large bowl with an electric mixer beat butter with 1/2 cup sugar until light and fluffy and beat in chocolate. Add yolks, one at a time, beating well after each addition. Stir in hazelnuts and flour.
Step 5
In another bowl with cleaned beaters beat whites with salt at medium speed until white, opaque, and beginning to hold their shape. Gradually add remaining 1/2 cup sugar, beating at high speed until whites hold soft (not stiff), slightly glossy peaks.
Step 6
Stir one fourth whites into chocolate mixture to lighten and fold in remaining whites gently but thoroughly until no streaks remain.
Step 7
Pour batter into pan and smooth top. Bake cake in middle of oven 35 to 45 minutes, or until a tester comes out clean. Invert cake onto a rack. After 5 minutes remove pan but leave cake on rack until cooled completely. With cake on rack set over a pan (to catch the drips), pour chocolate glaze over cake, allowing it to drip down outside and center.
Step 8
While glaze is still wet (to avoid cracking), transfer cake to a platter. When glaze is set, cover cake loosely with plastic wrap or keep under cake dome at room temperature until ready to serve.
Step 9
If cake is kept more than 1 day (before or after serving), it should be wrapped in plastic wrap and frozen. Bring cake to room temperature before serving.