Which lasagna cheese is a pasta filata, or stretched-curd, cheese?

Mozzarella is the lasagna cheese that is a pasta filata, or stretched-curd, cheese.

In the pasta filata method, freshly formed curds are immersed in very hot water or whey and then kneaded and stretched. This plasticises the curd, creating the supple, fibrous structure associated with mozzarella. The technique also explains why melted mozzarella can pull into strings rather than simply becoming a smooth, flowing sauce.

Mozzarella originated in southern Italy and is traditionally made from either cow’s milk or Italian Mediterranean buffalo milk. Cow’s-milk mozzarella is called fior di latte, while buffalo mozzarella is mozzarella di bufala. Fresh mozzarella is generally white, soft, and moist, and is usually eaten relatively soon after production rather than aged for a long period.

Pasta filata is a method, not a single cheese. Other stretched-curd cheeses include provolone, scamorza, caciocavallo, and burrata. In lasagna, mozzarella contributes moisture, mild dairy flavour, and a characteristic melt; Parmesan contributes a sharper, harder-grating quality, while ricotta contributes a soft filling texture. Mascarpone is creamy but is not the canonical stretched-curd answer.