1. Bring a large pot of salted water to a boil and cook the jumbo pasta shells until just al dente according to the package directions. Drain and place them on a tray so they do not stick together.

2. In a large mixing bowl, stir together the ricotta cheese, 1 cup of mozzarella, 1/2 cup of Parmesan, egg, minced garlic, Italian seasoning, parsley, salt, and black pepper until smooth and well combined.

3. Spread 1 1/2 cups of marinara sauce over the bottom of a 9×13 inch baking dish.

4. Spoon the ricotta mixture into each cooked shell and arrange the filled shells open side up in the baking dish.

5. Spoon the remaining marinara sauce over the shells, then sprinkle the top with the remaining 1 cup mozzarella and 1/4 cup Parmesan.

6. Cover the dish with foil and bake at 375°F for 25 minutes. Remove the foil and bake for another 10 minutes, or until the cheese is melted and the sauce is bubbling.

7. Let the shells rest for 5 minutes before serving, then garnish with extra parsley if you like.