Peel sweet potatoes, cut in half and slice. Cook covered till nearly done in very little boiling water. Take apples (sprinkle with lemon juice, if not tart). Grease baking dish, place alternate layers of sweet potatoes & apples. Sprinkle layers with quarter cup brown sugar, cinnamon, dot with butter & pour quarter cup water (or apple juice).
Bake 1 hour at 180ºC .