Preheat your oven to 350°F (175°C).

In a large pot of boiling salted water, cook the tortellini according to package instructions. Fresh tortellini takes about 3-5 minutes, while frozen might take a few extra minutes. Drain and set aside.

In a large bowl, combine the ricotta cheese, half of the mozzarella, grated Parmesan, Italian seasoning, salt, and pepper. Stir until well blended.

Add the cooked tortellini to the cheese mixture, ensuring every piece is coated nicely.

Spread half of the marinara sauce on the bottom of a greased 9x13-inch baking dish.

Pour the tortellini and cheese mixture over the sauce, then layer the remaining marinara sauce on top.

Sprinkle the remaining mozzarella cheese over the casserole.

Cover with aluminum foil and bake for 20 minutes.

Remove the foil and bake for an additional 10 minutes or until the cheese is bubbly and golden.

Remove from the oven, sprinkle with fresh basil, and serve hot.