The night before to prepare the cake, poppy seed is boiled and poured into a sieve to drain. The next day, margarine, 3 yolks and sugar well. Add poppy, then the flour with baking powder. Finally add the essence, beaten egg whites and hazelnuts. Pour into cake pan greased with butter and sprinkled with breadcrumbs. Bake in preheated moderate oven about 45-50 minutes.