At Taste of Persia NYC, a takeout counter tucked into a utilitarian pizzeria on 18th Street, Saeed Pourkay serves his justly fabled ash reshteh, a wondrous, wintry, outrageously thick Persian soup, along with rustic stews that have been simmered for hours, sometimes days. The food invokes the ancient splendors of the Spice Route, but comes in ordinary plastic bins; forks and napkins must be...