Dried plum is a traditional Chinese cooking material. Use mustard greens or other mustard kind of stems and leaves, dried salted made. It is a native Hakka dish. At the end of autumn and early winter, the mustard greens in the vegetable garden were mossed, with thin thumbs and flower buds on the top, shaped like autumn grapes, crisp and sweet. At this time, remove the choy sum and hang for a few days. When the leaves become soft, put them in a basin, sprinkle with salt, and rub them with your hands. When some vegetable juice oozes out, put them in a pottery urn. Place a layer of salt and use mustard leaves or bamboo shoot husks after filling. Seal the urn tightly. After ten and a half months, the dried plums were taken out and dried, and the dried plums were golden in color, salty and sour .