Bake in the center of the oven for 40 minutes, or until the apples release their liquid. Remove the dishes from the oven, uncover and baste the apples and sweet potatoes with the pan juices. Increase the oven temperature to 450° and place the dishes in the upper third of the oven. Continue baking for about 35 minutes longer, basting a few more times, until the sweet potatoes are tender and nicely glazed. Serve hot.