Brown the Sausage:
In a large pot or Dutch oven, cook the Italian sausage over medium heat until browned. Drain any excess grease.Sauté Aromatics:
Add the diced onion and cook for 3–4 minutes until softened. Stir in garlic and cook another 30 seconds until fragrant.Add Tomatoes and Broth:
Stir in diced tomatoes, chicken broth, water, Italian seasoning, and red pepper flakes. Bring to a gentle simmer.Cook the Tortellini:
Add the cheese tortellini and cook according to package directions, usually 5–7 minutes, until tender.Finish the Soup:
Stir in arugula and heavy cream, letting the greens wilt and the soup heat through. Season with salt and pepper to taste.Serve:
Ladle into bowls and top with freshly grated Parmesan cheese for a rich, creamy finish.
