1 egg, lightly beaten
1 (15 ounce) container ricotta cheese
1/4 cup grated Parmesan cheese
1 (28 ounce) jar meatless spaghetti sauce, divided
2 cups shredded part-skim mozzarella cheese, divided
1/4 cup grated Parmesan cheese, divided
2. Fill a large pot with lightly salted water and bring to a boil. Stir in ziti pasta and return to a boil. Cook pasta, stirring occasionally, until cooked through but still firm to the bite, about 11 minutes; drain.
3. Combine egg, ricotta cheese, and 1/4 cup Parmesan cheese in a bowl. Spread 1/3 the spaghetti sauce in prepared baking dish. Top with 1/2 the pasta, 1/2 the ricotta mixture, 1/3 the spaghetti sauce, 1/2 the mozzarella cheese, and 1/2 the Parmesan cheese; repeat layers. Top with remaining spaghetti sauce and Parmesan cheese; cover baking dish with aluminum foil.
4. Bake in preheated oven until heated through, 45 to 50 minutes.