Margaret Lai cooks her signature dish for her son and his family once a year. She fills the cavity of a duck with homemade plum sauce and steams it until tender. The sauce, made from purchased pickled plums, permeates the duck as it steams. After steaming, she empties the sauce into the pan juices and boils the mixture down to make a fruity sweet and sour sauce that complements the rich, moist duck. If you like roast duck, try the variation that follows.
