Ingredients:

   1       large        (1/4 lb) sweet potato or yam
   3       medium      Melrose or Golden  Delicious apples
   1       teaspoon   Lemon juice
   1       large         Leek
 1/4       cup         (1/2 stick) butter or -margarine, softened                    
 1/4      teaspoon   Salt
 1/8      teaspoon   Ground white pepper
 1/4       cup           Applejuice
   2       teaspoon   Packaged unseasoned  -bread crumbs                    
   1       tablespoon     Brown sugar

Instructions:
  Heat oven to 350'F.Peel and thinly slice sweet potato. Peel, core, and cut apples into 1/4-inch-thick slices. Place apples in bowl and add water to cover; add lemon Juice
.
Trim off top of leek 1 inch above white; discard top and root end. Cut leek lengthwise in half and clean well under running cold water. Thlnly slice leek crosswise.

Drain apples well; pat dry. Grease 1 1/2-quart casserole with 1 tablespoon butter.
Place one third of apples in bottom of casserole; top with one third of leek slices and one third of sweet potato. Season with salt and pepper. Repeat to make 2 more layers. Dot top of casserole with 2 tablespoons butter; pour apple juice over all. Cover tightly with lid or aluminum foil and bake 45 minutes.

Meanwhile, to make topping, in small saucepan, melt remaining 1 tablespoon butter; stir in bread crumbs and brown sugar until well combined. Uncover casserole and sprinkle with topping.
Bake uncovered 10 to 15 minutes longer or until potato slices are tender.

Serve casserole immediately.