Beat yolks with sugar until creamy. Add themashed bananas, beat well. Whip egg whites until stiff (in different bowl). Add cake meal, potato starch and salt to yolk mixture. Fold in egg whites into this mixture. Add flavoring fold in gently. Bake at 160ºC . for an hour --more or less--. Use an angle food cake pan. Cool upside down for about 30 minutes or until cooled. Cut in half with knife. Ice with real whipped cream or cool whip. Top with bananas and a few walnuts.