Bring a large pot of salted water to a boil. Add the manicotti tubes and cook until al dente, about 6–8 minutes; drain in a colander and rinse briefly with cool water.
Toss the drained tubes with 2 teaspoons olive oil to prevent sticking and set aside to cool slightly.
Preheat the oven to 400°F (200°C).
In a mixing bowl, combine 2 1/2 cups drained ricotta, 1 cup shredded mozzarella, 2/3 cup grated Parmesan, 1 teaspoon Italian seasoning, 1/3 cup chopped parsley, 1/3 cup chopped basil, and salt and pepper to taste until well blended.
Fill each manicotti tube with the cheese mixture using a piping bag or a spoon.
Spread 1 1/4 cups of marinara sauce across the bottom of a 9×13-inch baking dish. Arrange the filled manicotti over the sauce, then spoon the remaining marinara evenly over the tops. Sprinkle additional mozzarella on top as desired.
Cover the dish with foil and bake for 30 minutes. Remove the foil and bake uncovered for 10 more minutes, until the cheese is bubbly and lightly browned.
Let the baked manicotti rest a few minutes, garnish with additional basil, and serve.
