A mild–flavoured member of the onion family. The thick white stem of cultivated leeks are blanched by piling up dirt around them as they grow. Smaller leeks are best as the green tops are still tender. Some recipes ask for just the white part, but most of the leek can be used if it is young and the green leaves are not too tough. Leeks are particularly good in creamy sauces and soups, most famously vichyssoise. Like onions, they need to be cooked for a reasonable amount of time or they will be crunchy rather than tender and sweet; if overcooked, they will go slimy. Leeks can be boiled, steamed or braised in butter and cooked. Whole cooked leeks can be wrapped in pieces of ham or covered in a béchamel sauce and grilled. The leek is the national emblem of Wales.