Melt the butter in a large dutch oven (I use 5.5 quarts). Add the leeks, carrots, celery, salt and pepper. Cook for 5 minutes.
Add the chicken stock and wine, and bring to a boil. Add the chicken breasts. Turn the heat down to a simmer, and let it simmer for about 15 minutes, or until the chicken is cooked entirely.
Remove the chicken and shred. Raise the heat to a slow boil.
Add the mushrooms, green beans and noodles, and allow them to cook about 15 minutes or until the noodles are cooked through. Add the chicken back to the soup, and then add the fresh parsley. Season with salt and pepper to taste.