The topping side of pizza is built on the same principle that guides the dough: quality, balance, and restraint. Tomato sauce provides acidity, color, and a base for everything else. San Marzano tomatoes, a canned variety grown in Italy, are prized for their sweet, balanced flavor, and the true San Marzano DOP (Denominazione di Origine Protetta) designation protects against imitators. In Neapolitan tradition, the sauce is often simply raw crushed tomatoes with salt and sometimes olive oil or herbs; the rule is not to cook the sauce first, because the high-heat bake cooks it — and tomatoes actually brighten with brief exposure to high heat in the oven. The basil leaf is added before or after baking, depending on style. Some traditions place a thin layer of olive oil under the cheese to protect the dough from sogginess.
Cheese provides meltability, mild richness, and browning. Fior di latte — cow's milk fresh mozzarella — is the standard for Naples, while mozzarella di bufala, made from buffalo milk, is richer and more delicate. The Neapolitan approach is to hand-tear fresh mozzarella over the pie. In contrast, NY-style pizza uses shredded low-moisture whole milk mozzarella, which has less water and browns well during longer bakes. For best quality, fresh mozzarella should be bought the same day it is used, and a cheese drying step — patting fresh mozzarella dry with paper towels — reduces wateriness on the pie. Detroit-style pizza uses Wisconsin brick cheese pushed to the edges of the pan to create that signature frico. St. Louis-style is known for provel, a processed cheese blend unique to the region. Other cheeses appear as accents: Parmigiano-Reggiano, aged and hard, is grated over the top for depth; pecorino, made from sheep's milk, brings a sharper note.
The classics illustrate the principle of topping discipline — "less is more." Pizza Margherita, with tomato, mozzarella, basil, and olive oil, was reportedly named for Queen Margherita of Savoy in 1889, its colors echoing the Italian flag. Pizza marinara, with no cheese at all, is older still: tomato, garlic, oregano, and olive oil. White pizza skips the tomato, often using cheese, garlic, and oil, and pizza bianca goes further with just olive oil, salt, and sometimes rosemary. Spicy lovers gravitate to pizza alla diavola, with salami and chili. A typical pie uses about 80 to 120 grams of cheese, and toppings follow a hierarchy: sauce, then cheese, then toppings, then a finish of fresh herbs or a drizzle of extra virgin olive oil. Some toppings — like raw meats — must be pre-cooked; others — like most vegetables — cook on the pizza. Underdressing is a virtue, because too much topping turns a great crust soggy. The debate over pineapple on pizza is famously divisive; Italian purists generally object, but Hawaiian pizza, with pineapple and ham, was actually invented in Canada and remains popular worldwide. A finish drizzle of extra virgin olive oil — the first-press, highest-quality grade — adds flavor and visual sheen, though cheap oil is acceptable in dough where flavor matters less.