Wash yams or potatoes; drain but do not dry. Set in slow-cooking pot. Cover and cook on low for 4 to 6 hours (depending on size and shape). Peel and cut into quarters. Place in 2 quart casserole. In medium saucepan, melt butter; add sugar, cranberries, salt and pepper. Cook, stirring constantly, over medium heat until cranberries pop and sugar dissolves. Pour over yams in casserole.* Cover and bake in 350 F oven for 30 minutes.