Following these simple steps will guide you in preparing Creamy Seafood Stuffed Shells:

1. Preheat the Oven: Preheat your oven to 375°F (190°C). Prepare a baking dish by greasing it lightly with cooking spray or oil.
2. Cook the Pasta: Boil the pasta shells according to package instructions until al dente. Drain and set aside.
3. Prepare the Filling: In a large mixing bowl, combine ricotta cheese, chopped shrimp, chopped crab meat, half of the mozzarella cheese, and half of the Parmesan cheese. Add garlic powder, onion powder, salt, and pepper to taste. Mix well.
4. Stuff the Shells: Carefully fill each pasta shell with the seafood mixture, making sure to pack the filling well.
5. Make the Sauce: In a saucepan, heat the heavy cream over low heat. Add dried basil, dried parsley, salt, and pepper. Stir continuously until heated through. Remove from heat.
6. Assemble the Dish: Spread a thin layer of marinara sauce on the bottom of the prepared baking dish. Arrange the stuffed shells on top. Pour the creamy sauce over the stuffed shells, covering them generously.
7. Top with Cheese: Sprinkle the remaining mozzarella and Parmesan cheese over the top of the creamy sauce.
8. Bake: Cover the baking dish with aluminum foil and bake in the preheated oven for 15-20 minutes. Then remove the foil and bake for an additional 10 minutes until the cheese is bubbly and golden.
9. Let Cool: Once baked, remove from the oven and allow it to cool for a few minutes before serving to allow the filling to set.

By following this guide, you will master the preparation of these delightful seafood-stuffed shells.