Preheat your oven to 375°F and lightly grease a baking dish.
In a large bowl, mix together the marinara sauce, heavy cream, and Italian seasoning.
Add the tortellini to the sauce mixture and stir to coat.
Pour everything into the prepared baking dish and spread evenly.
Top with mozzarella and Parmesan cheese.
Bake uncovered for 20 to 25 minutes until bubbly and golden on top.
Remove from oven, let rest for a few minutes, then garnish with basil before serving.