Wikipedia
Jokpyeon is a jelly-like Korean traditional dish that is traditionally eaten around Seollal (Korean New Year's Day) throughout Korea. It is made by boiling offal or tough meat containing a great deal of collagen, such as the hooves, skull, and skin of a cow, for a long time. Shank and tendon can be added to make the dish as a supplement ingredient to enhance the taste. Through the boiling, the collagen becomes gelatin melted down like porridge. After filtered, it is poured into a square vessel and solidified in a cold place. Jokpyeon is sliced and is served with a dipping sauce such as choganjang (made from soy sauce and vinegar) or saujeotguk (extract from saujeot, salted fermented shrimp).
The dish largely depends on cow's hoof, so the name derives from jok ( 족, 足 foot) in Korean. The dish is sometimes categorized as a variety of muk, jelly mainly made from grain starch due to the similar appearance and characteristics.