These crescent-shaped turnovers are traditionally prepared for the Carnival season, and even though it is believed that they originated in the Apulia region, panzerotti are extremely popular all across southern Italy. They resemble small calzone pizzas—both in shape and the dough used for its preparation—but instead of being oven-baked, panzerotti are deep-fried, which is why they're also called calzoni fritti (fried calzones), pizze fritte (fried pizzas), or simply frittelle (fritters).
The classic panzerotto filling consists of merely tomatoes and mozzarella, but they can be filled with pretty much anything and in various combinations: prosciutto-mozzarella, pepperoni-provolone, spinach-ricotta, zucchini-mozzarella, onion-olives-tomatoes, speck-fontina, etc.