Burnt grass is a traditional snack in southern Fujian and Taiwan provinces, and is also known as cold noodles in some areas. In summer, locals eat frozen Xiancao and shaved ice, while in winter, they cook a bowl of warm, sticky Xiancao soup with various ingredients so that people can savor the delicious taste of Xiancao all year round. The name "Xiancao" is made from this herb. Fairy grass, also known as cactus, fairy grass, belongs to the genus Millet, and is somewhat similar in shape to mint. Orchids are terminal, with short stems, thin pedicels, and white or light red corollas. Fairy grass and mint. After people collect the fairy grass, they usually burn the fresh ones into dried fairy grass, and then boil them into fairy grass soup. As for the gelatinous form, it is formed because the soup is thickened and cooled by sweet potato flour. Dried cao xian can be made into cao xian jelly because it is rich in soluble polysaccharides. When the leaves are picked and rubbed, they feel sticky and slippery. Cao Xian polysaccharides are mainly found in the cell walls, and when dissolved in water, they can solidify into a gel, commonly known as Cao Xian gel. Boil the cool grass in water or add some seasoning such as dried cinnamon. Finally cook a pot of black soup. Add sugar at this time, and finally thicken with cornstarch. When cooled, it will solidify into black cactus and freeze. Dried cactus, because the Taiwanese pronunciation of "hot" is "burned", people in Taiwan Province simply named this special flavor of cactus soup "burned cactus", to show the authentic flavor of Taiwan Province.