The waldorf salad was invented at the Waldorf Hotel (now called the Waldorf-Astoria) in New York City in the early 1890's. Needless to say, it has been around for awhile. Traditionally the salad is made with chopped apples and celery with walnuts, mixed in a mayonnaise dressing and served on a bed of lettuce. I am not a fan of mayonnaise so I chose the sour cream route. Thick plain yogurt would also be delicious. To make this salad more protein rich, add chopped chicken or tofu. I think you are really going to love this recipe if you give it a try.