Saute the onions, carrots, celery and butter on medium heat in a large soup pot until they begin to soften.
Add the fresh garlic and saute for two minutes.
Add the flour and mix in/toss with the butter and vegetables until you get a paste like mixture. Continue cooking flour mixture (while stirring) for two minutes (until the flour gets a golden color).
Place the raw chicken breasts over the vegetables and then add the chicken stock and water.
Bring the soup to a boil (medium high heat) and then add all seasoning except the salt, pepper and rosemary, then reduce heat to medium and maintain a low boil (covered) for at least 30-45 minutes (depending on how much time you have).
Remove the chicken from the soup and shred or chop into large bite sized pieces then return the chicken to the soup.
Add the tortellini and cook at a low boil for another 15-20 minutes and then add the salt, pepper and fresh rosemary and continue to low boil for another 5-10 minutes.
Serve by topping with Parmesan cheese and enjoy!