In a large pot or Dutch oven, heat the olive oil over medium-high heat. Add the Italian sausage, breaking it up with a wooden spoon as it cooks. Cook for 6-8 minutes until browned and cooked through. Remove sausage from the pot and set aside.

In the same pot, add the diced onion, carrot, and celery. Sauté for about 5-7 minutes until softened. Stir occasionally to avoid burning. Add minced garlic and cook for another 1-2 minutes until fragrant.

Add chicken broth and diced tomatoes (with juices) to the pot. Bring mixture to a simmer over medium-high heat. Add Italian seasoning, salt, and black pepper. Let simmer for 10-15 minutes.

Add uncooked ditalini pasta to the pot, stirring to ensure it is evenly distributed in the broth. Reduce heat to medium and simmer for another 10-12 minutes until pasta is tender.

Once pasta is cooked, reduce heat to low and stir in heavy cream. Mix well until creamy. Add grated Parmesan cheese and stir until fully melted.

Return the cooked sausage to the pot, simmer for an additional 5 minutes to heat through. Adjust seasoning if needed. Serve hot garnished with chopped parsley.