For the stock: add all ingredients to a soup pot. Cook until chicken is tender, about 35 to 45 minutes. Remove chicken from pot and set aside to cool. Remove and discard bay leaves and onion. You should have approximately 3 quarts of stock. When chicken is cool enough to touch, pick bones clean, discarding bones, skin, and cartilage. Set chicken aside.
For the soup: bring stock back to a boil, add carrots, and cook for 3 minutes. Add celery and continue to cook for 5 to 10 minutes. Add egg noodles and cook according to directions on package. When noodles are done, add chicken, mushrooms, parsley, sherry and rosemary. Add Parmesan and cream, if using. Cook for another 2 minutes. Adjust seasoning, if needed, by adding seasoning salt and pepper. Enjoy along with a nice hot crusty loaf of French bread.