Arguably northern Thailand's most famous dish, khao soi can be found from unnamed holes-in-the-wall to five-star resorts, all peddling renditions of the "best" noodles money can buy.
For a fail-safe lunchtime introduction, Lam Duan Faham or Samoer Jai, both on Chiang Mai's Charoenrat Road, are terrific choices.
A glass of the herbal drink bai bua bok (Asian pennywort) helps you cool off after the spicy meal.