Lan Jia is widely regarded as having the best yì bāo (刈包) in Taiwan. What's yì bāo? Think of a savoury slow-braised pork hamburger with pickled mustard and ground peanuts stuffed inside a steamed bun. You'll find this place by the long queue snaking outside.
Take the MRT Exit 4 and turn left at the second lane (Lane 316).