Scalloped Potatoes

6 lbs. uncooked potatoes

3 C sliced onions, optional

1 1/2 T salt

3/4 to 1 C melted shortening

1 C all purpose flour

1 T salt

1 t white pepper

2 qts. scalded milk

1 1/2 C buttered crackers or bread crumbs

Peel and thinly slice potatoes. Cover with sliced onions. Place potatoes in baking pan and sprinkle with salt. Melt shortening. Add flour and stir until smooth. Add salt and pepper. Add scalded milk gradually, stirring constantly, and cook over low heat until smooth and thick. Pour hot white sauce over potatoes. Bake at 350 degrees for 1 hour, then cover with buttered crumbs and continue baking for another hour. Yield 25 servings.