The secret to the best, irresistible manicotti is to make them from scratch with homemade crespelles, which are basically Italian crepes. These are filled with spinach, egg and three cheeses and topped with homemade sauce. Filling and delicious!
Start by making the crespelles (see recipe link above)
Preheat oven to 375°F.
In a large bowl, combine ricotta, 1-1/2 cups of the mozzarella, egg, spinach, parmesan cheese, 1/2 teaspoon salt and pepper.
Fill each crespelle with 1/4 cup spinach filling and roll.
In a large baking dish, (or two smaller dishes) pour 1 cup of sauce on the bottom of the dish. Place rolled manicotti seem side down onto baking dish. Top with 1 1/2 cups more sauce and remaining mozzarella cheese.
Cover with foil and bake about about 25 minutes, until hot and bubbling, and the cheese is melted.