Prepare pasta according to package directions. Drain. Place in a bowl.
Toss with olive oil to prevent sticking. Set aside.
Place a large skillet over medium heat.
Add Italian sausage. Cook until browned and fully cooked, breaking it into small crumbles.
Remove from heat and let it cool slightly.
In a mixing bowl, combine cooked sausage, ricotta, mozzarella, Parmesan, garlic, Italian seasoning, crushed red pepper flakes, salt and pepper, to taste. Mix until well incorporated.
Using a small spoon or piping bag, carefully stuff each rigatoni with the sausage filling.
Set stuffed pasta aside on a baking sheet.
Place a saucepan over medium heat.
Add marinara sauce, heavy cream and Parmesan cheese. Stir until smooth and heated through.
Add chopped basil.
Taste. Add salt and pepper, to taste.
Spread a layer of the sauce on the bottom of a baking dish.
Arrange stuffed rigatoni on top in a single layer.
Pour the remaining sauce over the pasta.
Sprinkle generously with shredded mozzarella cheese.
Cover the dish with foil. (This dish can be done in advance up to this point. Refrigerate dish until ready to cook. Add an extra 10 minutes to the baking time if starting from cold.)
Preheat oven to 375°F.
Place in preheated oven and bake for 20 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Garnish with fresh parsley or basil.
Serve hot, preferably with a side of garlic bread and a crisp salad for the full Olive Garden experience!