Heat the oil in a thick-walled saucepan, add the onion, and fry until transparent. Add the meat, close the lid, and simmer for 20 minutes. Add turmeric, pepper, salt, cinnamon, tomatoes, and garlic. Simmer for 1.5 hours. Add jam (without the berries), lemon juice to taste (you are looking for a sweet-and-sour flavour), prunes, and grated gingerbread. Simmer for another half hour, then keep on the lowest heat for another hour. Remove the cinnamon stick before serving.