Jason Wang and his father, David Shi, began their success story out of longing: The dishes they first served out of a basement stall of the Golden Shopping Mall in Flushing, Queens, channeled signatures of their native Xi’an, the capital of China’s northwestern Shaanxi Province. Hand-ripped noodles with spicy cumin lamb (its complexly seasoned chile oil reflective of Xi’an’s Eastern point along the spice routes), liangpi “cold skin” noodles, and a lamb burger stuffed in a hamburger-bun-shaped bao became phenomenons. Now with over a dozen locations in three New York boroughs, the chain remains in the family, and the food — remarkable in its consistency and affordability — rightly persists as a cult obsession.