Boil dried fern root powder for 5 to 6 minutes. Fern root powder needs to be boiled in boiling water for 5 to 6 minutes until there is no hard stem heart, and then it is taken out and put into cold water for use; Fern root powder needs to be soaked in water for a long time before cooking, and it is best to soak it half an hour in advance, otherwise it will be difficult to cook, and it should not be cooked for more than 8 minutes, otherwise it will be difficult to eat. Dry fern root powder is a kind of food made from starch extracted from the roots of wild fern, which is similar in shape to vermicelli, but dark in color and smooth in taste. Fern root powder can not only be used as a delicious table food, but also rich in various trace elements and vitamins; In ancient China, bracken was regarded as a "delicacy", which could be used for plague, malaria, gastrointestinal discomfort, etc. The origin of fern root powder can be traced back to the Song Dynasty, when people began to make starch from fern roots, called "fern powder", and used it to make various foods.