Preheat the oven to 325 degrees F.
Coat bottom and bottom inch of sides of a 10-inch spring-form pan with softened butter. Layer 1 cup chopped hazelnuts on bottom of pan. In food processor or blender, combine remaining 1 cup hazelnuts, eggs, pudding mix, and melted butter. Process until well-mixed and nuts are ground fine. Pour into prepared pan. Bake about 20 minutes or until edges of torte are firm but center jiggles when pan is shaken. Remove from oven and cool 10 minutes. Release pan sides. Cool to lukewarm then transfer to serving plate and dust with cocoa powder and powdered sugar. Serve at warm or at room temperature.