Buying a large wedge of Parmesan and shredding it as needed can be a cost savings. Choose a piece that has even color. If the cheese is darker around the edges, it has already dried out.
1 16 oz. package ziti
2 tsp olive oil
1 28 oz. jar prepared pasta sauce
1 cup ricotta cheese
1/4 cup grated Parmesan cheese
6 oz shredded mozzarella cheese
Preheat oven to 350°F. Cook pasta according to package directions; drain. Combine pasta and olive oil in a large bowl; toss lightly. Grease a large baking dish.
Add pasta sauce to bowl; mix well. Spread 1/2 of pasta mixture in prepared baking dish.
Mix egg, ricotta and Parmesan in a bowl; spread over pasta. Sprinkle 1/2 of mozzarella over top. Spread remaining pasta mixture over top.
Sprinkle remaining mozzarella over pasta. Bake until heated through and cheese is bubbly, about 20 minutes.
Mozzarella is much easier to work with if it is very cold. Keep it in the refrigerator until the moment you need it, or put it in the freezer for 10 minutes to firm it up before shredding.