In a large Dutch oven, heat over medium heat and crumble the Italian sausage into the pot. Cook for about 5-7 minutes, stirring occasionally, until the sausage is fully browned and no longer pink. Drain excess grease.

Add the diced onion, Italian seasoning, salt, and black pepper to the sausage. Sauté for 1-2 minutes until the onion becomes translucent. Stir in the minced garlic and cook for an additional minute.

Pour in the petite diced tomatoes, chicken broth, and ditalini pasta, bringing the mixture to a gentle boil. Reduce heat slightly and cook for 8 minutes, or until pasta is al dente.

Reduce heat to medium-low. Stir in the softened cream cheese and grated Parmesan cheese until melted and the soup turns creamy, about 5 minutes.

Ladle the soup into bowls and top each serving with fresh basil.