A trip to the Chinatown precinct of any city provides ample proof that steamed dumplings will never go out of style. In this version, Sichuan pepper flavours the salt, which, in turn, flavours the stock. The primary flavours are provided by the chicken stock, Chinese wine and soy. If you prefer more of a Sichuan-pepper flavour, grate some pepper over the soup. You can also use full-bodied soy if you prefer. As with so many Asian dishes, the best ingredients of all will be fresh and in season.