Khao soi is northern Thailand's signature coconut curry noodle soup topped with crispy fried noodles. The 6 best khao soi shops: 1. Khao Soi Khun Yai (Old City, 50-60 THB, closes by 2 PM), 2. Khao Soi Mae Sai (Chang Phueak, 45-55 THB, thick rich broth), 3. Khao Soi Lam Duan Fah Ham (Fah Ham, 50-60 THB, one of the oldest), 4. Khao Soi Nimman (Nimman, 70-90 THB, air-conditioned), 5. Lamduan Faham Original (Charoen Rat, 50-60 THB), 6. Khao Soi Islam (halal, 50-70 THB, best beef version). Variations: classic chicken, beef, northern style, vegetarian. Eating etiquette: squeeze lime first, mix crispy noodles into broth, eat with spoon and fork, go before 2 PM.