In a large soup pot, heat 1 tablespoon of olive oil over medium heat until shimmering. Add the diced yellow onion and minced garlic, cooking for about 3-4 minutes until the onion is translucent and fragrant, stirring occasionally.

Stir in one can of diced tomatoes, including their juices, and 1 teaspoon of Italian seasoning to the pot. Allow the mixture to simmer for 2-3 minutes.

Pour in 4 cups of chicken broth, bringing the mixture to a gentle boil over medium-high heat. Reduce the heat to low and let it simmer for about 10 minutes.

Mix in 2 cups of cooked, shredded chicken, stirring well to combine, and heat through for about 5 minutes.

Lower the heat and gradually stir in 1 cup of heavy cream until the mixture is smooth and creamy, allowing it to heat gently for about 2-3 minutes.

Sprinkle in 1 cup of shredded Parmesan cheese, stirring constantly until it melts and incorporates fully into the soup.

Taste your soup, adding salt and pepper as needed. Ladle the warm soup into bowls, garnishing with freshly chopped parsley.