Fill a 4 qt. saucepan 2/3 full with water and bring to a boil. Trim ends of sweet potatoes and cut in half lengthwise. Drop potatoes into boiling water. When water returns to a boil, cook potatoes for 30 minutes.
While potatoes are cooking, peel, core and slice the apples. Put the apple slices in a medium bowl. In a small bowl, combine sugar and spices. Pour sugar mixture over apples. Stir to cover apples. Set aside.
When the potatoes are par-boiled, remove them from the pan. Use a knife and fork to remove the skins. Slice the sweet potatoes in 1/4 in. slices.
In a 2 qt. casserole, pour a little butter in the bottom. Rotate the dish to coat the sides. Layer 1/2 the sweet potatoes. Follow with a layer of sugared apples. Repeat. Pour the remaining butter over the layers. Bake at 350 degrees for 1 hour.
Notes: You can spray the casserole with non-stick spray if you prefer.
I don't cover this casserole. I like the tender crispness of the apples. You can use a covered casserole. The dish will cook a little quicker (45-50 min.) and the apples will be softer. Or you could cover the casserole with foil.
I like to lay the apple slices in patterns, i.e. herringbone for a rectangular dish, circles for a round dish, just for fun.