Measure 4 cups of boiled and riced sweet potatoes into a mixing bowl. Beat in thoroughly 1/4 cup each of butter, half and half. Add 1/4 teaspoon nutmeg and gradually add 1/4 cup rum. Season to taste with salt and pepper. Heap the sweet potatoes into a casserole and sprinkle surface with melted butter and 1 tablespoon grated orange rind. Bake in hot oven, 400 degree, until top is lightly browned.