Chinese white cabbage is more popularly known as bok choy; it has been grown in China for centuries and has a light, fresh slightly mustardy taste and requires little cooking. Although there are many varieties, the most common and best known is the one with a long, smooth, milky-white stem and large crinkly, dark-green leaves. The size of the plant indicates how tender it is. The smaller the better, especially in the summer, when the hot weather toughens the stalks. In Hong Kong, bok choy is used in soup or stir-fried. Store in the bottom of your refrigerator. Look for firm, crisp stalks and unblemished leaves.