In a large pot, heat a drizzle of olive oil over medium heat. Add the Italian sausage and cook it for about 5-7 minutes, breaking it apart as it browns.

Once the sausage is browned, stir in chopped onions, cooking for 3-4 minutes until they become translucent. Add minced garlic and sauté for another minute until fragrant.

Pour in the chicken broth and add the diced tomatoes along with the fresh spinach. Bring to a gentle simmer for about 5 minutes.

Stir in the heavy cream, red pepper flakes, salt, and pepper. Let it simmer for an additional 5 minutes.

Ladle the soup into warm bowls, garnishing with freshly grated Parmesan cheese and parsley if desired.