Brown the sausage: In a large pot or Dutch oven, cook the sausage over medium heat until browned and cooked through. Transfer to a plate and set aside.
Sauté the vegetables: In the same pot, add olive oil if needed and sauté the onion and carrots for 4–5 minutes until softened. Stir in garlic and cook for 1 more minute.
Add potatoes and tomatoes: Stir in the potatoes and diced tomatoes. Cook for another 2–3 minutes to release flavor.
Pour in broth and season: Add the chicken broth, Italian seasoning, and sausage back to the pot. Bring to a boil, then reduce heat and simmer for 15 minutes or until potatoes are tender.
Stir in pasta: Add the ditalini and simmer uncovered for 8–10 minutes, or until pasta is just tender.
Make it creamy: Stir in the heavy cream and parmesan cheese. Simmer on low heat for 5 more minutes, stirring gently.
Season and finish: Taste and adjust seasoning with salt and pepper as needed. Remove from heat.
Serve warm: Ladle soup into bowls, garnish with chopped parsley and a sprinkle of parmesan, and enjoy hot.