This thin, moist cake, filled with tender young zucchini and the unmistakable fragrance of basil, is a traditional cake from the coastal town of Viareggio in northern Tuscany. It was traditionally baked by old sailors with zucchini from their vegetable gardens. Now, come summertime, when zucchini flood market stalls and overtake backyard gardens, locals still turn to this beloved regional recipe. Its name refers to its homely appearance: Scarpaccia means something like “large and ugly shoe,” as the cake is flat and about the thickness of an old shoe. It’s not too sweet, with an unusual green flavor, and stays pleasantly moist thanks to the thinly sliced zucchini added to a simple batter of flour, milk, eggs, sugar, and olive oil. If you’re not feeling adventurous enough to make this sweet version, know that in Camaiore, a nearby town, locals make a savory version of zucchini scarpaccia. Naturally, the two …