1Preheat the oven to 180 degrees.
2Break egg yolks in a mixing bowl.
3With a fork, roer in vanilla citroen peeling.
4Sprinkle flour over egg yolk.
5In another bowl, beat the egg whites with a pinch of salt until they cling to beater.
6Add the sugar and beat stiff.
7Fold in the egg yolk mixture and bake in well greased baking pan for about 12 minutes.
8Sprinkle with powdered sugar and serve.