In a large pot over medium heat, pour the olive oil once the oil is hot add in the onion, garlic and rosemary. Saute for 5 minutes or until the onion is soft.
Add in the diced tomatoes, tomato sauce, broth, oregano, basil, salt and pepper, and heavy cream and give it a really good stir. Bring to a low simmer for 20 minutes covered. Stir frequently.
Add in the tortellini and cook an additional 12 - 14 minutes, or until the tortellini is completely cooked. Once finished stir in parmesan cheese.