Heat olive oil in a large stock pot over medium -medium high heat. Once it becomes bubbly and fragrant, add the celery, carrots, onion poultry seasoning, and salt. Sauté until the vegetables are tender, about 5-10 minutes.
Pour 8 cups of the broth and heavy cream into the vegetables, then add the noodles and chicken and submerge them in the liquid. Bring the pot to a boil, then reduce heat to low and allow soup to simmer for 8-10 minutes or until the noodles are al dente.
While the soup simmers, mix the cornstarch and water until the cornstarch is completely dissolved.
Pour the cornstarch mixture into the soup slowly while stirring continuously. Once it is all combined, let it simmer an additional 2-3 minutes or until it starts to thicken. Stir in additional broth if you want the soup to be thinner.(see notes)
Garnish with fresh parsley if desired. Serve hot!
