1/4 c. nonfat dry milk powder
2 c. skim milk
2 tbsp. butter
1/4 c. flour
1/2 tsp. ea. salt and pepper
1 3/4 lb. potatoes, pared 1/4" slices (about 4 potatoes)
1 1/2 c. thin sliced onions
3/4 c. shredded fat free Cheddar cheese
1/4 c. soft bread crumbs

Dissolve milk powder in skim milk, set aside. Melt butter in heavy pan, add flour. Stir well, cook 1 minute, will be lumpy. Gradually add milk, stirring constantly with wire whisk, until thickened. Add salt and pepper. Remove from heat. Coat a 12x8 baking dish with cooking spray. Spread 1/4 cup of sauce in dish, and half of each, potatoes, onions and cheese, a layer of sauce, repeat except for cheese. Cover and bake at 375 degrees for 1 hour or until potatoes are tender. Uncover, add remaining cheese and bread crumbs. Coat with cooking spray lightly. Bake an additional 5 minutes.