Chocolate Ganache Filling
For cake preheat oven to 350° F and grease and line bottom and sides of a 9-inch springform pan with parchment paper. Sift together flour, hazelnuts, baking powder and salt. In a separate bowl, stir vanilla into sour cream and set aside. Cream butter and sugar together until light and fluffy. Add eggs, one at a time, stirring well after each addition. Add flour and sour cream mixtures alternately, until all ingredients have been incorporated. Scrape into prepared pan and bake for 50 to 60 minutes, until a tester inserted in the center of the cake comes out clean. Allow to cool on a rack.
For syrup, simmer sugar and water for 5 minutes and remove from heat. Stir in liqueur and allow to cool.
For filling, heat cream to just below a simmer and pour over chocolate. Let sit for 1 minute, add butter and stir gently until evenly melted. Stir in liqueur. To cool ganache to spreadable consistency, spoon about 3 to 4 ounces of ganache onto a marble board or clean countertop and spread out. Immediately scrape up and spread out again, too cool. Add ganache back to pot and stir in (this should thicken the ganache a little). Repeat process 2 or 3 times, until ganache is thick enough to spread with a palette knife, but not too firm. If too firm, just heat gently over low heat to re-melt.
To assemble torte, slice cake horizontally into 3 discs. Place first disc on plate and brush with syrup. Spread about ½ cup of ganache over layer and top with second disc and brush with syrup. Spread ganache over and top with last disc of cake and brush with syrup. Spread final layer of ganache over entire cake. Top with roughly chopped hazelnuts and chill until ready to serve.
Yield: 1 9-inch torte