Grease the tin with sunflower oil. Onions and mushrooms cut into slices or circles. In greased tray placed first dense layer of half the onions and half the top layer of mushrooms. On them shall be arranged steaks, which are sprinkled with spices to taste (if you marinated without spices). Top again with a layer of the rest of the mushrooms and onions. The dish is baked in a preheated oven at 250C degrees for about an hour - hour and 15 minutes.