Tteok (Hangul: 떡) (Korean pronunciation: [tʼʌk]; also spelled ddeock, duk, dduck, dduk, or thuck) is a class of Korean rice cakes made with glutinous rice flour (also known as sweet rice or chapssal), by steaming. Normal rice flour can be used for some kinds of tteok. There are hundreds of different kinds of tteok eaten year round. In Korea it is customary to eat tteok guk (tteok soup) on New Year's Day and sweet tteok at weddings and on birthdays. It is often considered a celebratory food and can range from rather elaborate versions with nuts and fruits down to the plain-flavored tteok used in home cooking. Some common ingredients for many kinds of tteok are mung bean, red bean, and sweet red bean paste, Korean mugwort, jujube and other dried fruits, sesame seeds and oil, sugar, and pine nuts.