Five-Cheese Jumbo Shells

Ingredients

• 24 uncooked jumbo pasta shells
• 1 tablespoon olive oil
• 1 medium zucchini, shredded and squeezed dry
• 1/2 pound baby portobello mushrooms, chopped
• 1 medium onion, finely chopped
• 2 cups reduced-fat ricotta cheese
• 1/2 cup shredded part-skim mozzarella cheese
• 1/2 cup shredded provolone cheese
• 1/2 cup grated Romano cheese
• 1 large egg, lightly beaten
• 1 teaspoon Italian seasoning
• 1/2 teaspoon crushed red pepper flakes
• 1 jar (24 ounces) meatless spaghetti sauce
• 1/4 cup grated Parmesan cheese