Preparation Preheat oven to 350°F. Butter 8-inch-diameter springform pan with 2 3/4-inch-high sides. Line bottom of pan with parchment paper. Butter parchment. Wrap outside of pan with foil. Finely grind hazelnuts in processor. Stir chocolate and butter in heavy medium saucepan over low heat until smooth. Cool chocolate mixture to room temperature. Using electric mixer, beat yolks and sugar in large bowl until thick and pale yellow, about 5 minutes. Fold in cooled chocolate mixture, then hazelnuts. Transfer batter to prepared pan. Smooth top. Bake until cake is set and appears dry but tester comes out with very moist crumbs attached, about 45 minutes. Transfer to rack. Lightly press down any raised edges of cake. Cool completely. Run small knife around sides of pan to loosen cake. Remove pan sides. Invert cake onto platter. Remove pan bottom. Peel off parchment. Slide waxed paper strips under cake to protect platter. Using icing spatula, spread thin coating of Chocolate Glaze over top and sides of cake. Rewarm remaining glaze over low heat if necessary. Pour glaze in pool over center of cake; spread over top and sides. Remove waxed paper strips. (Can be prepared 1 day ahead. Cover with cake dome and refrigerate. Let stand 1 hour at room temperature before serving.)
Preparation Preheat oven to 350°F. Butter 8-inch-diameter springform pan with 2 3/4-inch-high sides. Line bottom of pan with parchment paper. Butter parchment. Wrap outside of pan with foil. Finely grind hazelnuts in processor. Stir chocolate and butter in heavy medium saucepan over low heat until smooth. Cool chocolate mixture to room temperature. Using electric mixer, beat yolks and sugar in large bowl until thick and pale yellow, about 5 minutes. Fold in cooled chocolate mixture, then hazelnuts. Transfer batter to prepared pan. Smooth top. Bake until cake is set and appears dry but tester comes out with very moist crumbs attached, about 45 minutes. Transfer to rack. Lightly press down any raised edges of cake. Cool completely. Run small knife around sides of pan to loosen cake. Remove pan sides. Invert cake onto platter. Remove pan bottom. Peel off parchment. Slide waxed paper strips under cake to protect platter. Using icing spatula, spread thin coating of Chocolate Glaze over top and sides of cake. Rewarm remaining glaze over low heat if necessary. Pour glaze in pool over center of cake; spread over top and sides. Remove waxed paper strips. (Can be prepared 1 day ahead. Cover with cake dome and refrigerate. Let stand 1 hour at room temperature before serving.)