WHEN IT’S cold out and your breath comes out as small white puffs, the food stands on the street are warm and inviting, drawing you in with promises of warm delicious food. Perhaps the most popular food stand is the one that sells bung-eo-ppang, a fish-shaped bread pastry with red bean paste. Standing under the soft yellow light, you hand over a crumpled bill. In the middle of the cold, dark street, you bite into the head of the pastry, drawing a sound of indignation from your friend who believes you have to eat it tail-first.