There are as many variations of the ubiquitous spicy Thai green papaya salad as there are families in the country’s northern regions, as if it was each clan’s honorary insignia. At Som Tum Udon in Chiang Mai’s northwest corner, you can create your own crunchy legacy by customizing a personal fantasy of your ultimate som tum: will it be + seafood + lashings of passion fruit + salted duck’s egg? Or + century egg + fermented baby crab + mango? The little stall that could, started by two sisters, is now an open-air rustic sprawl featuring a line of som tum superstars, all natives of Isaan province where the dish originated. The flurry of forearms pounding, sauces and juices squirting, and roasted peanuts tossing through the air can make for heart-stopping entertainment, although your appetite will continue to grow exponentially. And because this is Thailand, extremities in flavor are in order: complement the som tum you’ve freshly designed with a grilled Isaan specialty, such as the deep fire pork rib (really, pork belly), which I’ll gladly burn in hell for. At the self-service counter, pile up on fresh herbs from mint to basil for putting out som tum fires in your mouth, wash it all down with a fresh fruit slushy elixir, and please, please save room for the khanom buang (crispy pancakes filled with coconut cream and candied egg yolk) cart across the soi for dessert.