HUNGARIAN HAZELNUT TORTE

Steps:

• For cake:
• Preheat oven to 350°F. Butter and flour 9-inch-diameter springform pan. Line bottom with parchment paper. Blend first 4 ingredients in processor until nuts are ground as fine as flour.
• Using electric mixer, beat egg yolks, 1/3 cup sugar, and vanilla in large bowl until mixture falls in heavy ribbon when beaters are lifted, about 5 minutes. Using clean dry beaters, beat egg whites in another large bowl until soft peaks form. Gradually add 1/3 cup sugar, beating until stiff but not dry. Fold 1/4 of whites into yolk mixture to lighten. Fold in remaining whites. Sift half of flour mixture over; fold in gently. Sift remaining flour mixture over and fold in, adding any nuts from sifter. Drizzle butter over batter, folding in gently (do not overmix or batter will deflate).
• Transfer batter to prepared pan; bake until tester inserted into center comes out clean, about 35 minutes. Transfer pan to rack; cool cake 10 minutes. Cut around pan sides to loosen cake; release pan sides. Invert cake onto rack. Remove pan bottom and parchment paper. Cool.
• For buttercream:
• Place cornstarch in heavy small saucepan. Gradually add milk, stirring until cornstarch dissolves. Whisk in egg yolks. Whisk constantly over medium-high heat until custard comes to boil and thickens, about 3 minutes. Transfer to large bowl. Press plastic wrap onto surface of custard. Chill 30 minutes.
• Finely grind 1 cup nuts with powdered sugar in processor, about 30 seconds. Using electric mixer, beat vanilla into custard. Beat in butter, 1 piece at a time, then beat in ground nut mixture in 4 additions. Refrigerate until firm enough to spread, stirring often, about 30 minutes.
• Stir apricot preserves in small saucepan over medium heat for 1 minute. Push preserves, including fruit pieces, through strainer into small bowl. Cool.
• Finely chop 1/2 cup hazelnuts. Using long serrated knife, cut cake horizontally in half. Place 1 layer, cut side up, on 8-inch-diameter tart pan bottom or cardboard round. Spread evenly with apricot preserves. Top with second layer, cut side down. Transfer 3/4 cup buttercream to pastry bag fitted with large star tip. Spread remaining buttercream over top and sides of cake. Press 1/2 cup chopped hazelnuts onto sides of cake.
• Pipe 12 rosettes around top edge of torte. Place 1 hazelnut and 1 apricot sliver into each rosette. Refrigerate until buttercream sets, at least 1 hour. (Can be made 1 day ahead. Cover with cake dome; keep chilled. Let stand at room temperature 1 hour before serving.)