This recipe demonstrates the ambassadorial powers of barbecue. I got it from a Pakistani sea captain, one Mushtaque Ahmad, whom I met on a Singapore Airlines flight from Singapore to Bangkok. (The captain was on his way home to Karachi after seven months at sea.) Our conversation began about the O. J. Simpson trial—the first one—and eventually led to cooking. Here’s how the captain prepares a spicy, yogurt-marinated Pakistani favorite: chicken tikka.