I first had the saffron ice cream called bastani akbar mashti in 1978 in Tehran’s Grand Bazaar. I was in Iran with my mother, the last trip I would make to her native country, mere months before the Revolution that began what has become forty years of acrimony between our two nations.

But on that day, the Bazaar was packed with shoppers seeking out everything from daily staples to luxury goods. Everywhere I looked there was a riot of color, fabric and food. The smells of roasting kebabs filled the air mingling with the scent of tea brewed with cardamom.

The ice cream, delicately yellow and aromatic with saffron and rosewater was punctuated with the occasional crunch of pistachios—a prized Iranian export—and bits of frozen cream. Even though I’ve had versions of it since, none have ever been as good—either too light on the saffron, too sweet, or omitting the frozen cream nuggets.

That all changed when I visited Green Leaf Catering Truck, the mobile restaurant of Dariush Rose and his son Samuel.