Now that we have our ingredients ready, let’s dive into the cooking process. Follow these steps to create your own Spinach and Cheese Stuffed Shells:

1. Preheat the Oven: Start by preheating your oven to 375°F (190°C).
2. Cook the Pasta Shells: Bring a large pot of salted water to a boil. Add the jumbo pasta shells and cook them until they are al dente, usually about 9-10 minutes. Drain and set aside to cool slightly.
3. Prepare the Spinach: In a large skillet, heat olive oil over medium heat. Add the minced garlic and sauté until fragrant (about 1 minute). Add the chopped spinach and cook until wilted, about 4-5 minutes. Remove from heat and let it cool.
4. Make the Cheese Filling: In a large mixing bowl, combine ricotta cheese, 1 1/2 cups of shredded mozzarella, Parmesan cheese, egg, salt, black pepper, and a pinch of nutmeg if using. Add the cooled spinach mixture and mix until all ingredients are well combined.
5. Stuff the Shells: Take each cooked pasta shell and fill it with approximately 2 tablespoons of the cheese and spinach mixture. Repeat until all shells are filled.
6. Assemble the Dish: Spread 1 cup of marinara sauce evenly on the bottom of a 9×13-inch baking dish. Arrange the stuffed shells in the dish, open side up. Pour the remaining marinara sauce over the shells.
7. Add Cheese Topping: Sprinkle the remaining 1/2 cup of mozzarella cheese over the top of the shells.
8. Bake: Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
9. Garnish and Serve: Remove from the oven and let cool for a few minutes. Garnish with fresh basil before serving.