Sweet potato casserole

1 large cansweet potatoes
3/4 c brown sugar
1/2 c sugar
1 can pie sliced apples
1 1/2 T cornstartch
1/4 t cinnamon
2 T butter
1/4 t salt
1/2 cup broken pecans
Miniature marshmallows

Combine sugars, salt, cornstarch, and cinnamon. Stir 1 c water into dry mixture. Place in saucepan over medium heat. Cook to boiling. Continue cooking approximately 2 minutes. Add apples. Place sweet potatoes in baking dish. Pour syrup mixture over potatoes. Pus apple slices in between potato wedges. Sprinkle pecans over potatoes, blending in potato mixture. Bake at 350 for 1 hour. Just before baking time is over remove casserole from oven. Sprikle with marshmallows on top return to oven and brown at 375 degrees.