Beat the egg whites with a mixer with sugar until they become thick foam. Add to carefully beaten yolks, flour, vanilla and lemon zest and mix gently by hand with a stirrer. Pour the mixture, arranged in three portions / hills, in an oiled baking dish with dimensions 20x30cm. Bake in preheated oven at 220 degrees for 9 minutes. While baking, the oven should not be opened. dessert is served hot and eaten immediately. Garnish with jam or sauce of raspberries, strawberries or cranberries. You also have her recipe, almost the same, but with different quantities: http://www.gutekueche.at/rezepte/4878/original-salzburger-nockerl.html