Some folks use cool whip or yogurt, but I prefer the original recipe. I would suggest adding about 1-2 tbsp of sugar to the dressing for that hint of sweetness. Seedless red grapes or dried cranberries may also be halved and added for color and texture.
2 cups mayonnaise
1 tablespoon cider vinegar (optional, but gives it a bit of "zing.")
2-1/2 tablespoons lemon juice
Dash of salt
4 diced apples (Granny Smith, Gala or Red Delicious)
3 stalks celery, diced
1 cup chopped walnuts
Whisk to blend dressing ingredients and set aside. Chop all salad ingredients evenly. Mix dressing with salad ingredients. Chill until ready to serve.