Peel and finely grate the onion; add it to the meat with the parsley, half the salt and the pepper. With wet hands mix thoroughly and shape into small balls. Heat the oil in a pan, add the kebab balls and place over a low heat. Cover the pan and leave for fifteen minutes until the meat juices have reduced, leaving only oil. Mix the yogurt with the remaining salt and pepper. Arrange the kebabs on a serving dish, pour yogurt on top and serve hot.