Choy Sum

Choy sum or choi sum (Chinese: 菜心) literally means "vegetable heart" in Cantonese. While frequently used to describe edible stem of either of the two varieties of Chinese cabbage, usually the soft inner core of bok choy with the tougher outer leaves removed, the term can be applied to the "heart"–the soft core or flowering stem–of almost any vegetable such as kai-lan, including non-traditionally East Asian greens such as broccoli. Outside of China, the Cantonese spelling of choy sum is more common than the standard Mandarin pinyin spelling càixīn due to the greater influence of Cantonese cuisine in the West.