There are many grades of these wonderful mushrooms said to have been cultivated for more than a thousand years in southern China. Black or brown in colour, they add a particular flavour and aroma to Chinese dishes. The best, and most popular in China, are very large ones with a lighter colour and a highly cracked surface; these are usually the most expensive. Chinese markets specialising in dried food carry all grades heaped in mounds, with the most expensive mushrooms elaborately boxed, sometimes in plastic. Fresh mushrooms (popularly known by their Japanese name, Shiitake) are not an adequate substitute and the Chinese almost never use them fresh, preferring the dried version’s distinct, robust, smoky flavours, and the way they absorb sauces, taking on a succulent texture. They are used as seasonings, finely chopped and combined with meats, fish, and shellfish. Keep them stored in an air-tight jar in a cool, dry place.