Sicilians are renowned for making a very unique style of pizza known as sfincione in standard Italian (Florentine) dialect, better known in Sicily as sfincuini. The name itself literally means "large puff", or mass of dough, taken from the Greek word for sponge. And spongy is certainly one way to describe the slow rising process of the dough, which always contains olive oil.
Sfinci is a colloidal term used throughout the peninsula of Italy referring to puffs of dough that have been deep-fried, whether they are made savory or sweet. The savory versions are often stuffed with such ingredients as anchovies, cheese, broccoli and cauliflower, while the sweeter varieties are either split open to be filled with custard or left whole to be rolled in granulated sugar or sprinked with confectioners' sugar. They are often interchangably called zeppole, although the dough preparations are quite different. Nowadays sfinci is specifically made by preparing a cream puff batter and frying small fritters of this before filling or simply coating with sugar. (when baked in the traditional manner, they are known as bigne.)
Traditionally, sfinciuni dough is made with flour, water, yeast, salt, olive oil and often a tiny amount of sugar to promote the yeast activity. It is then left to rise quite slowly, often overnight in the refrigerator before it is divided. A square or rectangular baking sheet is coated with olive oil, slightly more than normal since the dough is to be coated with oil on both sides, pressed with the fingers to almost fit the shape of the pan and left to rise once again. This will allow the dough to be stretched evenly to fit along the sides of the pan without shrinking back.
Though a large number of variations exist in Sicily as in America, perhaps the most famous is the Palermo version, topped with thinly sliced onions, olives, salted anchovy filets, oregano, tomato, olive oil and bread brumbs for a crunchy top layer. Grated cheese, such as Pecorino Romano or caciocavallo may also be added. The key here is to use a scant topping of each ingredient so that the dough may rise while baking and the toppings baked in, rather than simply placed on top. Once the sfinciuni is finished, it is set to cool on a rack to be eaten warm, never hot, or at room temperature. Therefore, in Sicily a sfincuini deviates from a traditional Neapolitan pizza in that it resembles more or less a focaccia than pizza, and is referred to as such when purchased at a local focacceria.
From Sicily the sfinciuni emigrated to the United States along with a massive influx of Italians from the southern regions of Rome, Campania, Calabria, and of course Sicily herself. It is unclear as to where the Sicilian take on pizza got its start, though culinary historians largely agree that it was in Brooklyn, New York and most likely during the Great Depression. From the Italian neighborhood homes in Brooklyn a version of sfinciuni began to feature on the menu of many prominent Neapolitan pizzerie. From there it took on the same formula as a typical Neapolitan pie: mozzarella, tomato "sauce", grated hard cheeses and olive oil, though it maintained the familiar square or rectangular shape of a true "Sicilian pizza." This style of pizza is still typically made and enjoyed in Brooklyn and the remaining bouroughs. And while it may not be traditional, it greatly impacted the diversity and genius of pizzamaking prominently featured all over the world.