Creating the perfect Three Cheese Manicotti can be effortless if you follow these simple steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C).
2. Cook the Manicotti: Boil the manicotti shells according to package instructions until al dente. Drain and set aside.
3. Prepare the Cheese Filling: In a mixing bowl, combine ricotta cheese, mozzarella cheese, Parmesan cheese, egg, oregano, salt, and black pepper. Mix until well combined.
4. Fill the Shells: Using a spoon or piping bag, carefully fill each manicotti shell with the cheese mixture.
5. Prepare the Baking Dish: Spread 1 cup of marinara sauce at the bottom of a 9×13 inch baking dish.
6. Arrange the Manicotti: Place the filled manicotti shells in a single layer over the marinara sauce.
7. Top with Sauce: Pour the remaining marinara sauce over the filled shells, ensuring they are well covered.
8. Add Cheese: Sprinkle any remaining mozzarella and Parmesan cheese on top for extra flavor.
9. Cover and Bake: Cover the baking dish with aluminum foil and bake for 25 minutes.
10. Uncover and Finish Baking: Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and golden.
11. Garnish and Serve: Remove from the oven and let it cool for a few minutes. Garnish with fresh basil before serving.

These straightforward steps will guide you in creating this incredible Three Cheese Manicotti effortlessly.