In a large pot, add the chicken, chicken broth, water, salt, and pepper. Bring to a boil over medium-high heat.

Reduce heat and simmer for about 15 minutes, or until the chicken is cooked through.

Add the carrots, celery, onion, and garlic to the pot. Cook for an additional 10 minutes, until the vegetables are tender.

Stir in the heavy cream and the cornstarch mixture. Cook for another 5 minutes, stirring frequently until the soup thickens.

Adjust seasoning with more salt and pepper if needed.

Ladle the soup into bowls and garnish with fresh parsley before serving.