There is a recipe for homemade ranch dressing in the latest "Joy of Cooking"...as I remember it calls for mayo and sour cream or yogurt...but there are non dairy subs for those. Is younger DD just lactose intolerant, or does she need to be casein free ? Can she tolerate soy ? If she can tolerate soy and/or casein there are loads of good subs for the sour cream or any milk.