In a small, unassuming pizzeria in a shopping plaza on the outskirts of Rome, I ate the greatest slice of pizza I’ve ever had. It was rectangular, about ¾ inch high, slicked with a nearly imperceptible varnish of tomato sauce, and topped with soppressata, oozy provolone and mozzarella cheeses, and paper-thin slices of potato. The sauce, soppressata, and cheeses combined for a salty-savory punch, and the potatoes—not something I would normally think to include on pizza—were lightly crisped, browned, and curled at the edges. But the best part of this pizza was the crust: full of irregularly sized holes, tender and chewy in equal measure, with an audibly crisp yet delicate bottom and a yeasty, tangy, complex flavor.
This memorable slice turned out to be a Roman invention known as…