Chinese-Style Plum Sauce

More liquid and less fiery than Indian chutneys, to which it is closely related, this Chinese dip-sauce is most often served with roast pork and spring rolls. If you have not had the opportunity to eat in a fine Chinese restaurant, you may have encountered only the sickly-sweet, garlic-laden pink substance labeled “duck sauce” but bearing no resemblance whatsoever to the pungent, fruity real thing. Incidentally, you don’t need to wait to cook a Chinese meal to savor this sauce; it may be se