Coffee Montage Seongnae is a roastery cafe in an alley near Gangdong-gu Office in Seoul that serves lattes and flat whites. It roasts its own beans, and the latte and flat white are its main menu items. The shop gets crowded from noon to 1 p.m. when takeout orders peak, and there are not many tables inside. The seating is uncomfortable, so staying for a long time is difficult.