Brown the Italian sausage in a skillet over medium heat, breaking it into bite-sized pieces. Drain any excess grease.
Transfer the cooked sausage to the crockpot.
Add the onion, carrots, celery, garlic, chicken broth, potatoes, Italian seasoning, basil, salt, and black pepper.
Cover and cook on Low for 6 to 7 hours or High for 3 to 4 hours, until the potatoes are fork-tender.
About 30 minutes before serving, stir in the softened cream cheese until melted.
Add the heavy cream and grated Parmesan cheese, stirring until smooth and creamy.
Stir in the fresh spinach and cook for another 10 to 15 minutes until wilted.
Taste and adjust seasoning if needed.
Serve hot, garnished with chopped parsley and extra Parmesan cheese.