Put the flour into a pot, add water, salt and black sesame seeds, mix and knead repeatedly to make dough, and then simmer for 20 minutes. Roll the dough into thin slices with a rolling pin, the thinner the better, then cut the dough into rectangular pieces with a width of 5cm and a length of 10cm, and then overlap each other. Cut three parallel slits with a length of 5cm in the middle of the overlapped dough pieces with a knife, take one end of a rectangular dough piece to pass through the slits, and then pull it back to its original position. Heat the oil in the pot with medium fire. When the heat reaches 60%, put the processed dough pieces in, fry them slowly for a while with medium fire, and when bubbles swell on the surface and the surface is golden yellow, take out and drain the oil.