Follow these steps to create the amazing Easy Stuffed Shells:

1. Cook the Shells: In a large pot of salted boiling water, cook the pasta shells according to package instructions until al dente. Drain and set aside to cool slightly.
2. Preheat the Oven: While the pasta is cooking, preheat your oven to 375°F (190°C).
3. Prepare the Filling: In a large bowl, combine ricotta cheese, 1/2 cup mozzarella cheese, grated Parmesan cheese, egg, chopped spinach, minced garlic, oregano, salt, and pepper. Mix until well combined.
4. Stuff the Shells: Spoon the ricotta mixture into each pasta shell, making sure to fill them generously.
5. Prepare the Baking Dish: Spread 1 cup of marinara sauce evenly across the bottom of a 9×13-inch baking dish.
6. Arrange the Shells: Place the stuffed shells in the baking dish, open side up.
7. Add More Sauce: Pour the remaining marinara sauce over the shells, making sure they are well covered.
8. Sprinkle Cheese: Top the shells with the remaining mozzarella cheese.
9. Cover with Foil: Tent the dish with aluminum foil (making sure it doesn’t touch the cheese) to prevent burning.
10. Bake: Place the dish in the preheated oven and bake for 25 minutes. Remove the foil and bake for an additional 10–15 minutes or until the cheese is melted and bubbly.
11. Cool: Let the dish cool for about 10-15 minutes before serving.
12. Garnish: If desired, sprinkle with fresh basil before serving.

With these straightforward steps, you’ll have an incredible plate of Easy Stuffed Shells ready to impress.