Cream of Mushroom Soup

12 ounces fresh mushrooms, sliced
1 tablespoon butter or margarine
3 cups chicken broth
2 tablespoons chopped onion
2 tablespoons flour
1 cup sour cream
1 cup half-and-half
Salt and pepper

In skillet saute mushrooms in butter along with onions. Place in crock pot. Add chicken broth, salt and pepper; stir well. Cover and cook on LOW for 6 to 10 hours or on HIGH for 2 1/2 to 3 hours.

About 30 minutes before serving, turn crock pot to HIGH setting.

Mix flour and sour cream. Add to crock pot with half-and-half. Cook until slightly thickened.