For cake, preheat oven to 350. Cut waxed paper to line bottoms of 3 baking pans, 4 1/2 x 8 1/2 inches. Separate eggs. Beat white til stiff but not dry; set aside. Mix yolks with next 5 ingredients in large bowl and beat until fluffy. fold pecans into yolk mixture. Stir in about 1/4 whites to loosen batter. Gently fold in remaining whites. Divide among baking pans and bake until cake pulls away from sides of pans. Center of cakes will still be moist, about 25 minutes. Let cool. Whip cream until stiff. Beat in orange zest. Slice each cake horizontally to form 2 layers. Frost with cream between each layer, stacking to make 6 layers. Refrigerate torte. For Icing, melt chocolate in double boiler. Mix egg yolks, sugar and sour cream in small bowl. Beat til smooth. Add to melted chocolate, whisking constantly and cook about 2 minutes. Frost cold torte while icing is still warm. Makes 12 to 14 servings.
Legends, Norman, Oklahoma