Beat 6 egg yolks. Add crumbled feta cheese and yoghurt. Beat the egg whites of hard snow. Combine the two mixtures - gently mixed by stirring with a spatula or spoon. Melt pure butter. Brush Spread a filo pastry sheet, bend both longer end in the middle. Spread with butter. Put 3 tbsp of the mixture. Bending again two longer end in the middle. Again, brush with butter. Starting from one shorter end of the triangle to bend the end of the list - see drawing. Brush with butter and remaining yolk and sprinkle with cheese. Bake in preheated oven about 20 minutes. * Egg white must be broken down into hard snow because by the end of the winding of the banitsi, the mixture must remain fluffy. * It is with all kinds of filo pastry sheets - finely rolled, hand-rolled. Once sold etc Sofia peel - were soft and elastic implicated eggs. They became best. * The banitsi remain fluffy even after cool. If you like sweet and savory - you can finally sprinkle with powdered sugar. * Source mother in law is my aunt.