Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with cooking spray or olive oil.
In a large bowl, combine the tortellini, marinara sauce, and ricotta (if using). Stir until well coated.
Pour the mixture into the prepared baking dish. Top with mozzarella and parmesan cheeses. Sprinkle with Italian seasoning, and add salt and pepper if desired.
Cover with foil and bake for 20 minutes. Remove the foil and bake for another 5–10 minutes, or until cheese is melted and lightly browned.
Let it sit for a few minutes out of the oven. Sprinkle with fresh parsley or basil before serving, if desired.