Boil sweet potatoes until half-cooked, 15 to 20 minutes. Peel and slice thinly.
Mix sugar, spices and salt
Place a layer of sweet potatoes in pastry-lined 9" pie pan, sprinkle with some of the sugar-spice mixture and dot with a little butter. Continue until all ingredients are used, dotting top with butter. Add cream. Adjust top crust; flute edges and c