Widely used in Hong Kong, this is a thick, dark-brownish red sauce that is made from soya beans, vinegar, sugar, spices and other flavourings. It is sweet and spicy and is widely used in southern Chinese cookery. In the West, it is often used as a sauce for Peking Duck instead of the traditional sweet bean sauce. Hoisin sauce is sold in tins and jars (it is sometimes also called barbecue sauce) and is available in Chinese shops and some supermarkets. Refrigerated, it keeps indefinitely.