Legend has it that Zhang Zhongjing was an official in Changsha, and when he retired in his later years, it happened to catch up with that winter. The wind is biting and the snow is falling. On the edge of the Baihe River, he saw many homeless people who were sallow and emaciated, and their clothes were uncovered. Because of the cold, their ears are frozen and rotten, and their hearts are very uncomfortable.
Later, after research, he developed a therapeutic prescription that can keep out the cold, which is called "Quhan Joule Decoction". The first "Quhan Joule Soup" is actually to put mutton and some medicines for dispelling cold in a pot, take it out and chop it up after cooking, wrap it in a flour bag to look like an ear, then put it in a pot and cook the stuffed dough with the original soup. When the dough bag is finished, it looks like an ear. Because its function is to prevent the ear from freezing, he named it "Joule".
He asked his disciples to give each poor person a bowl of soup and two "burnt ears". People eat "burnt ears" and drink soup, and they are all hot and their ears are burning. No one frostbites their ears any more. Therefore, people left the custom of eating jiaozi on the solstice of winter.