Cook potatoes and grate in large pieces grater. The butter melts. Egg whites were separated from the yolks. Potatoes mixed with egg yolks, yogurt, grated cheese, melted butter, salt, pepper, nutmeg. Pour the mixture into greased with butter and flour pan. Egg whites are broken down into snow and extruded as roses on the potato mixture. Bake in a moderate oven for 30 minutes, taking care not to burn egg whites (10-15 minutes bake only on the lower wire). Serve with season salad or yogurt with dill and garlic.