Gim Seobang Chapssaltteok sells glutinous rice cakes filled with red bean paste and nuts at the Lotte Castle shopping arcade in Daeyeon-dong, Busan. The cakes are chewy and not very sweet, with several varieties beyond the standard chapssaltteok. Reserve a day in advance to pick up takeout when the shop opens in the morning. Leftover cakes can be frozen and naturally thawed while remaining chewy.