The butter should be at room temperature and mix with powdered sugar fluffy cream. Were added one by one, 6 yolk and add the lemon juice. Add flour with baking powder and vanilla. Finally add the beaten egg whites. Mix thoroughly and pour into a greased and sprinkled with flour pan. Sprinkle with chopped walnuts and sugar. Bake in preheated oven at 180 C until ready. When cool cut into crescents with a glass or cookie cutters.