Here's the thing: mozzarella and parmesan are made from different types of milk, which affects their taste and texture. Mozzarella is made from cow's milk, while parmesan is made from a combination of cow's and sheep's milk. This difference in milk gives parmesan its distinctive nutty flavor.
But, let's get real - sometimes you just don't have parmesan on hand, and you're craving that cheesy goodness. In a pinch, you can use mozzarella as a substitute, but keep in mind it won't have the same sharp flavor. Mozzarella is better suited for dishes where you want a creamy, melty texture.