Grease 8-inch spring form pan or non-stick cake pan. With a mixer, beat eggs, ground nuts, sugar and salt until light and fluffy, about 5 to 7 minutes. Add butter; beat until smooth. Gently fold in flour. Pour into prepared pan; sprinkle with chopped nuts. Bake in a 350 oven for 25 to 30 minutes, or until top springs back when gently pressed. Run thin spatula around sides of pan to loosen cake; cool before removing rim.
Hazelnut Industry and The Hazelnut Marketing Board