In operation for more than 70 years, Lam Duan is the oldest khao soi shop in Chiang Mai and the original purveyor of Northern Thailand's signature dish. Khao Soi is so iconic of the northern Thailand city it is often called “Chiang Mai noodles.” This noodle soup likely originated in Burma and was brought over by Chinese Muslims traders during the 18th and 19th centuries. Hearty egg noodles swim in a coconut milk curry soup with tender chicken or beef. It’s topped with crispy noodles, cilantro and served with lime wedges, pickled mustard, sliced shallots and chili paste. Serious Eats features Lam Duan restaurant as their benchmark destination in Chiang Mai and, yes, it is a quality stopover. The issue is the dish is loaded with coconut milk, which is a crowd pleaser for visitors but not locals. The real deal is richer, tangier and spicier than this ultra-sweet version. Also, try the pork satay and the kanom jeen nam ngiaw.