Khao Soi Mae Sai for best khao soi (40 THB). SP Chicken for rotisserie chicken and sticky rice. Huen Phen for authentic Northern Thai (closed Wed). Street food at Chang Phueak Gate night market is incredible and cheap!
Kao Soy Lamduan Fahham is the best khao soi in town. 60 THB for a huge bowl. Opens 9am-4pm daily. Cash only. Get there before 11am to avoid crowds. It is near the old city east gate.