Peel the onion and cut into thin slices. Clean, wash and chop the peppers and zucchini. Wash the meat and dab dry. Heat 1 tablespoon of oil. Fry the medallions in it for 2 minutes on each side.
Season with salt and pepper and put aside. Add the rest of the oil to the pan. Fry the prepared vegetables for about 10 minutes, turning them over. Season with salt, pepper and dried
Season it with oregano. Stir in chunky tomatoes. Pour into an ovenproof dish. Place medallions on top. Grate cheese over them. Bake in the preheated oven (electric cooker: 225 ° C/ gas: level 4) for about 5 minutes. Serve sprinkled with fresh oregano