sweet potatoes & apples, baked

2 to 3 granny smith apples (peeled + sliced in rounds, seeds removed)
juice of 1 lemon
2 to 3 red skinned sweet potatoes (peeled + sliced in rounds)
2 tablespoons butter (cut into small pieces for dotting)
1/4 cup brown sugar
1 teaspoon pumpkin pie spice
2 tablespoons real maple syrup
1/4 cup apple juice

Preheat the oven to 400 degrees. Toss apple slices in lemon juice and set aside. In a small bowl mix together brown sugar and pumpkin pie spice. In another small bowl whisk together apple juice and maple syrup. Set aside. Rub the bottom of a large baking dish with butter. Alternate layering apples and sweet potatoes in the dish packing in as many as possible. They shrink up so you want them really overlapping and packed tightly. Pour apple juice mixture all over the top of the layers and then sprinkle with brown sugar mixture. Finish by dotting the top with pieces of butter. Bake covered with aluminum foil for 35 to 45 minutes then test for doneness. When the sweet potatoes and apples start to get tender, take the foil off and let the top caramelize in the oven for 5 minutes. Be sure not to over bake apples.