From butter to toppings, Korean rice cakes — called "tteok" — are enjoying a heyday of flavor innovation. As various rice cake desserts lead this year’s food trends, even spawning the term “tteok-run” to refer to lining up before a store opens to secure the trendy treats, convenience store chains are jumping on the bandwagon. According to purchasing data from market research firm Embrain, estimated spending on rice cakes reached 151.9 billion won ($112 million) from September last year to August this year, up 31.2 percent from the previous year. Spending increased by more than 20 percent across all age groups, with purchases by people in their 20s and younger surging 45.5 percent. The rise reflects a growing number of young consumers willing to wait in long lines to try rice cake desserts that have gone viral on social media. Following the Shanghai-style butter rice cake and Gwangju’s Changeok rice cakes, which gained popularity this spring, a variety of rice cake desserts have recently taken off almost simultaneously. These include Hanjeongseon's fruit-filled glutinous ric