Peel the potatoes, quarter lengthwise. Boil until almost done (not fall apart). Drain, place in 9x13 baking pan, sprinkle LIBERALLY with garlic salt. While potatoes are boiling, mix butter,cheese,sour cream and half and half. (I melt in microwave) Stir so the cheese will not burn. Pour cheese mixture over potatoes, cover and bake at 350* 1/2 hour, uncover and cook another 1/2 hour.
These are a must at our family gatherings. The original recipe says to boil potatoes in skins and then peel, but I have found they work well this way.