The Secret Behind a Beloved Palestinian Dessert

Mastic feels like stones between the fingers and turns pliant between the teeth — although “if you bite it, it cracks,” the French Palestinian chef Fadi Kattan says. Under a pestle, it crumbles into a shimmery dust. Stir this into liquid, and there’s a slight thickening, a sudden heaviness, verging on syrup. Kattan, a founder and owner of the restaurant Akub in London, likes to add ground mastic to the juices…