Beat the egg yolks with the sugar for about 5-10 minutes or until a standby melting sugar. Then add the oil and mix again for 1 minute. Then add the yogurt, which is mixed with baking powder. Add vanilla. Finally, put the flour, which screened at least twice and stirring with stirrers without turning on the mixer. After having asked the flour, then stir in slow speed. Anoint form cake with a piece of butter, which is melted in seconds on the stove instead of flour and sprinkle with sugar. Put in cold oven to 180 C for about 50 minutes without opening. * Optional you can add cocoa, walnuts, orange peel.