Preparation:

1. Preheat the Oven: Preheat your oven to 375°F (190°C). Preheating the oven is essential for even cooking.

2. Prepare the Spinach: If using fresh spinach, wash it thoroughly to remove any dirt or grit, then chop it finely. If using frozen spinach, ensure it’s fully thawed and squeeze out as much excess water as possible. This step is crucial for preventing a watery filling. You can use your hands to squeeze the spinach, or wrap it in a clean kitchen towel and twist it to remove the moisture.

Cook the Pasta Shells:

3. Boil the Water: In a large pot of boiling salted water, cook the jumbo pasta shells until they are al dente (slightly firm to the bite). Adding salt to the water helps to season the pasta. Cooking the shells al dente is important because they will continue to cook in the oven, and you don’t want them to become mushy.

4. Drain and Set Aside: Drain the cooked pasta shells thoroughly and set them aside. Rinsing them with cold water immediately after draining stops the cooking process and prevents them from sticking together. You can also lightly drizzle them with olive oil to prevent sticking.

Prepare the Filling:

5. Sauté the Garlic: In a skillet, heat the olive oil over medium heat. Add the minced garlic and sauté until fragrant, about 30 seconds. Be careful not to burn the garlic, as it can become bitter. Sautéing the garlic in olive oil releases its aromatic compounds and adds depth of flavor to the filling.

6. Add the Spinach: Add the spinach (fresh or thawed and drained frozen) to the skillet and cook until wilted (if using fresh) or heated through (if using frozen). Season with salt and pepper. Cooking the spinach removes excess moisture and concentrates its flavor.

7. Combine Filling Ingredients: In a mixing bowl, combine the ricotta cheese, mozzarella cheese, Parmesan cheese, egg, nutmeg (if using), and the sautéed spinach mixture. Mix until all ingredients are well incorporated. The egg acts as a binder, holding the filling together during baking.

Assemble the Dish:

8. Prepare the Baking Dish: Spread a thin layer of marinara sauce at the bottom of a baking dish (a 9×13 inch dish is ideal). This prevents the shells from sticking to the dish and adds a layer of flavor.

9. Stuff the Shells: Carefully stuff each pasta shell with the cheese and spinach mixture using a spoon or a small spatula. Be generous with the filling, but don’t overstuff the shells to the point where they might burst during baking. Stuff the shells seam side up to prevent the filling from spilling out during baking.

10. Arrange in Dish: Place the stuffed shells seam side up in the baking dish, arranging them in a single layer. If you have extra filling, you can spoon it over the shells.

11. Top with Sauce and Cheese: Pour the remaining marinara sauce evenly over the stuffed shells, ensuring that all the shells are covered. Sprinkle additional mozzarella cheese on top. The extra mozzarella will create a bubbly and golden crust.

Bake:

12. Cover and Bake: Cover the baking dish tightly with aluminum foil and bake in the preheated oven for 25 minutes. Covering the dish with foil helps to trap the moisture and prevents the shells from drying out during baking.

13. Uncover and Bake: Remove the foil and continue baking for an additional 10 minutes, or until the cheese is bubbly, melted, and lightly golden brown. Baking the shells uncovered for the last 10 minutes allows the cheese to melt and brown beautifully.

Serve:

14. Garnish and Serve: Garnish the baked stuffed shells with fresh basil or parsley before serving. Fresh herbs add a vibrant touch of flavor and visual appeal. Serve the stuffed shells hot and enjoy!