Sweet Potatoes and Apples

6 medium sweet potatoes
5 apples (Golden delicious) peeled and sliced
1 cup sugar
2 cups water
3 tablespoons cornstarch
1 teaspoon salt
juice of 1/2 lemon or 1/2 tablespoon lemon juice concentrate
1/2 cup butter

Boil sweet potatoes until partially done: cool, peel, and slice. Place sweet potatoes and apples alternately into pan or baking dish, starting with apples. Combine and cook (on stove top) the remaining ingredients until thick. Pour over the sweet potatoes and apples. Bake for 1 hour at 350 degrees.