Beef-Stuffed Shells with Creamy Ricotta Filling

Cook jumbo shells 2 minutes less than package directions. Drain, rinse with cold water, and set aside.
Brown ground beef with onion until no longer pink, about 5-6 minutes.
Add garlic and Italian seasoning, cook 30 seconds more. Season with salt and pepper. Cool slightly.
Combine ricotta, 1 cup mozzarella, Parmesan, egg, and parsley in a bowl. Fold in cooled beef mixture.
Spread 1 cup marinara in a 9×13 baking dish. Fill shells with beef-cheese mixture and arrange in dish.
Cover with remaining sauce and sprinkle with 1½ cups mozzarella.
Bake covered at 375°F for 25 minutes, then uncovered 10-15 minutes until bubbly.
Rest 5-10 minutes before serving. Garnish with fresh herbs if desired.