Mandu guk

Mandu-guk or dumpling soup is a variety of Korean soup (guk) made by boiling mandu (dumplings) in a beef broth or anchovy broth mixed with beaten egg. According to the 14th century records of Goryeosa (고려사), mandu had already been introduced via Central Asia during the Goryeo era. Mandu was called sanghwa (쌍화) or gyoja (교자) until the mid-Joseon Dynasty and became a local specialty of the Pyongan and Hamgyong regions, as both wheat and buckwheat — the main ingredients for flour — were mainly cultivated in the north. Mandu was made and cooked in various ways, including manduguk. In the Korean royal court, the dish was called byeongsi (병시) while in Eumsik dimibang, a Joseon Dynasty cookbook, it was called "seokryutang" (석류탕). The exact era when manduguk got its modern name is unknown.

Source: Wikipedia