Preheat oven to 350°. Mix wafer crumbs, hazelnuts and melted butter; press onto bottom of an ungreased 9-in. springform pan., Beat cream cheese and sugar until smooth. Beat in cooled chocolate, then sour cream, extracts and salt. Add eggs; beat on low speed just until blended. Pour over crust. Place pan on a baking sheet., Bake until center is almost set, 60-65 minutes. Cool on a wire rack 10 minutes. Loosen sides from pan with a knife; cool 1 hour longer. Refrigerate 3 hours. , For glaze, in a microwave, melt chocolate with cream; stir until smooth. Stir in vanilla. Spread over chilled cheesecake. Refrigerate, covered, overnight. Remove rim from pan. If desired, serve with whipped cream and additional hazelnuts.