3      tablespoons   margarine
   3      tablespoons   flour
     1/4  teaspoon      pepper
   2 1/2  cups          milk
   1      large         onion -- chopped
   5      cups          potatoes -- cooked and sliced
   2      cups          ham -- cooked and diced
     1/2  cup           cheddar cheese -- shredded
Preheat oven to 400 degrees.  Grease a 2-quart casserole.  Melt
margarine; stir in flour and pepper.  Add milk and cook until
thickened, stirring constantly.  Remove from heat and add onion,
potatoes, and ham.  Pour into prepared pan.  Top with cheddar cheese.
Bake for 45 minutes.