Choy sum, also known as Yu Choy or you cai, is a leafy green vegetable with long, tender stalks. A member of the brassica family (which also includes bok choy, broccoli, brussels sprouts, cauliflower, cabbage, collard greens, kale, and napa cabbage), yu choy features oval-shaped leaves that vary in tones from bright green to a dark verdant hue. They are available throughout the year, but peak season runs from spring through the autumn. A versatile vegetable, yu choy lends itself to a variety of cooking techniques beyond blanching and sautéeing, including steaming and stir-frying. Its small, bright yellow flowers are also prized for their sweet taste. Yu choy is often on dim sum menus and pairs well with hearty proteins such as pork and poultry. Description thanks to Food and Wine