In a heavy 3 to 4 qt saucepan, bring stock to a boil over high heat. Stir in the milookhiyya, tomato paste, salt and a few grindings of the pepper and reduce the heat to low. Stirring occasionally, simmer for about 20 minutes, or until the milookhiyya has dissolved and the soup is thick and smooth. With a mortar and pestle or the back of a spoon, mash the garlic and coriander to a smooth paste. In a small skillet, heat the oil over moderate heat. When hot, add the garlic and coriander and, stirring constantly, cook for a minute or two until the garlic is lightly browned. Add the entire contents of the skillet to the soup and, stirring all the time, simmer for 2 or 3 minutes more. Taste for seasoning and serve at once from a heated tureen. In Egypt, milookhiyya is often accompanied by hot cooked rice and sliced boiled chicken or game birds, presented separately on individual plates.