Cawl Mamgu refers to one of Wales food which uses leek as a basic ingredient. Cawl Mamgu is a rich soup or stew with lamb or mutton, turnips or swedes, carrots, potatoes, parsnips, onions, and leeks. The leek was once designated as one of the national emblems of Wales, and is used in a number of dishes. Leek is worn on St. Davids Day, March 1, a national holiday.