You can't come to the Gongguan area of Taipei and not try two of Taiwan's most traditional snack foods: boba and guabao. Lan Jia Guabao is very well-known in the area for their guabao, which has been described (oddly) as a Taiwanese burger.
Guabao, a very traditional Taiwanese snack, consists of braised pork belly, pickled mustard greens, peanut powder, and cilantro all in a steamed bun. For those that dislike peanut or cilantro, baos can be adjusted to your preference.
At Lan Jia, you have 5 options for buns: all lean meat, more lean than fat, half and half, more fat than lean, and all fat. I always go half and half.
If you like a good broth, definitely try their pork bone and corn soup. It has the best corn/beef flavor and is great for a cold day or if you just want something to warm your belly.
Cash only. Closed Mondays. Open late til around 11pm/midnight-ish.