In Cantonese cuisine it is categorized as a tong sui or sweet soup, hence the Chinese name. The soup is usually thin, but potent in taste. The recipe is simple, consisting of boiling the sweet potato for a long time with rock candy. Sweet potato is one of the most commonly found and abundant vegetable grown in China. With its simple recipe and large crop supply, sweet potato soup is one of the most accessible and affordable tong sui in the region.