Boil 6 yams; peel and slice lengthwise (making 4 slices). Layer slices in a large baking pan. Sprinkle a layer of sugar over all slices. Next, sprinkle a layer of cinnamon over all. Melt a stick of butter and pour over all. Now drizzle white Karo syrup, approximately 1 cup, over all yams. Bake in a low 225 degree oven for 30 minutes. Serves 10.