Order the pandoro, an Italian brioche piled with a snowdrift of powdered sugar, plus the salt bread (소금빵). The original Onion location, set inside a former 1970s warehouse that was once a supermarket then a metal factory. Bare grey walls, communal tables, a small garden. Other Onion branches in Anguk, Mia, and Gwanggyo, but the Seongsu warehouse is the one that started the brand.