Preheat the oven to 350°F (175°C). Grease a 9x9-inch baking dish.

Boil a large pot of salted water and cook the pasta shells 1-2 minutes less than package directions. Drain and set aside.

In a large skillet, brown the ground beef over medium heat for about 6-8 minutes.

Drain off excess fat if needed. Add the chopped onion and sauté for 3-4 minutes until softened. Stir in minced garlic and cook for 30-45 seconds.

Pour in the cream (or softened cream cheese) and the marinara sauce. Stir until smooth, then season with salt, pepper, and Italian seasoning.

Simmer the sauce for 2-3 minutes to thicken slightly.

Fold the cooked pasta into the beef-cream sauce until well combined.

Transfer the mixture to the prepared baking dish and top with shredded cheese.

Bake for 25-30 minutes until the cheese is melted and bubbly.

Let rest for 5 minutes before serving, garnished with chopped parsley.