Use a good baking apple, like Mcintosh or Cortland, that will hold up well during cooking.
1 can (32 ounces) sweet potatoes, sliced lengthwise, or 4 cups sliced sweet potatoes
2 cups apple slices, peeled, and cut 1/4 inch thick
3/4 cup maple syrup
1/4 cup butter, melted
1 teaspoon salt
Place potato slices in a greased casserole dish. Arrange apple slices on top. Combine syrup, butter, and salt, and pour over potatoes and apples. Cover and bake at 350 degrees F for 45 minutes. Uncover and continue baking until apples are tender. Basting improves the flavor; add more maple syrup if desired.