The song is Selling Tangyuan

Tangyuan, also known as Yuanxiao, Tangtuan and Floating Yuanzi, is one of the representatives of traditional snacks in China, and it is a spherical food made of glutinous rice flour. There are usually fillings, cooked and eaten with soup. At the same time, it is also the most distinctive food of the Lantern Festival with a long history.

it is said that glutinous rice balls originated in the song dynasty. At that time, Mingzhou (now Ningbo City, Zhejiang Province) began to eat a novel food, that is, black sesame seeds and lard were used as stuffing, a little white sugar was added, and glutinous rice flour was rubbed into a circle outside. After cooking, it tasted sweet and delicious, and it was very interesting. Because this glutinous rice dumpling is floating and heavy when cooked in a pot, it was originally called "Floating Yuanzi", and later it was renamed as glutinous rice dumpling in some areas. However, glutinous rice balls symbolize a better family reunion, and eating glutinous rice balls means family happiness and reunion in the new year, so it is a must-have food for the Lantern Festival on the fifteenth day of the first month. In some areas in the south, people will also get used to eating glutinous rice balls during the Spring Festival, instead of jiaozi.