Combine Sour Cream, Heavy Cream And Salt In A Bowl. Layer 1/2 The Potatoes Eggs And Ham In A 2 Quart Casserole Dish. Top With 1/2 The Sour Cream Mix. Repeat With The Other 1/2 Ingredients. Mix Crackers, Butter And Onion Salt And Sprinkle On Top Of The Casserole.