Preheat oven to 375°F and grease dish.
Mix ricotta, spinach, egg, garlic, Italian seasoning, salt, and pepper.
Boil manicotti shells until al dente.
Rinse and pat shells dry.
Spread sauce on bottom of baking dish.
Stuff shells with ricotta filling.
Arrange in dish, top with sauce and cheeses.
Cover with foil and bake 25 minutes.
Remove foil, bake 10–15 minutes more.
Rest 5 minutes, garnish with basil, and serve hot.