Cream of Mushroom Soup

This is a very good soup.

1/2 cup butter or margarine
4 cups thinly sliced mushrooms (I added 6 cups)
1/2 cup finely chopped onion
1/2 cup flour
1 1/2 teaspoons salt
1/2 teaspoon pepper
1/4 teaspoon nutmeg
4 cups water
2 cups light cream or half-and-half
2 cups sour cream
1 (10 1/4 ounce can) chicken broth
1/2 cup chopped parsley

Melt butter or margarine in large skillet over medium heat; add mushrooms and onion and saut