In a large Dutch oven, heat over medium-high heat and crumble in the Italian sausage. Cook for 5-7 minutes until the sausage is well-browned and cooked through, stirring occasionally.

Add the diced yellow onion, carrots, and celery to the pot with the browned sausage. Sauté for 5-7 minutes until the vegetables are softened. Stir in the minced garlic and cook for an additional 30-60 seconds.

Pour in the diced tomatoes (with their juices) and low-sodium chicken broth into the pot, mixing everything well. Sprinkle in the Italian seasoning and crushed red pepper flakes, and season with kosher salt and black pepper. Bring to a gentle boil, then reduce heat and let it simmer for about 10 minutes.

Once simmered, add the ditalini pasta and cook uncovered for 8-10 minutes, or until al dente. Stir occasionally.

Lower the heat and stir in the freshly grated Parmesan cheese until it melts. If using heavy cream and baby spinach, stir them in now, adjusting the seasoning to taste.

Ladle the soup into bowls and garnish with extra Parmesan cheese and chopped fresh parsley. Enjoy!