Follow these straightforward steps to create incredible stuffed shells that will wow your family and friends:

1. Preheat Oven: Start by preheating your oven to 375°F (190°C).
2. Cook Pasta: Boil the pasta shells according to package instructions until al dente. Drain and set aside.
3. Prepare Filling: In a bowl, combine ricotta cheese, 1 cup of mozzarella cheese, Parmesan cheese, egg, basil, garlic powder, salt, and pepper. Mix until well combined.
4. Stuff the Shells: Using a spoon, fill each cooked pasta shell with the cheese mixture. Place filled shells in a greased baking dish.
5. Add Sauce: Pour marinara sauce evenly over the stuffed shells, ensuring they are well coated.
6. Top with Cheese: Sprinkle the remaining ½ cup of mozzarella cheese over the sauce.
7. Bake: Cover the baking dish with aluminum foil and bake the shells for 30 minutes. Remove the foil and bake for an additional 15 minutes, until the cheese is bubbly and slightly golden.
8. Cool: Once done, let the dish cool for a few minutes before serving.

By following these instructions closely, you will be able to create a delightful meal that showcases the beauty of Italian cooking!