As a child reared on northern Chinese cooking, jiaozi were food to dream about, a birthday treat. I used to watch Lim, our cook, and the amah gossiping with much cackling laughter as they filled tray after tray with these savoury dumplings, plump as little goldfish in their pleated cases of white dough. Fillings vary in detail, but a mixture of finely chopped pork, prawns and Chinese cabbage, spiked with soy sauce and aromatic sesame oil, is a constant. Sealed throughout co