2 tbsp. onion, chopped
1/4 c. butter
1/4 c. flour
1 tsp. salt
1/2 tsp. dry mustard
Dash of pepper
1 1/2 c. milk
8 oz. Cheddar cheese, shredded
1/2 lb. ham, cut into slices
6 c. potato slices, cooked

Saute onion in butter. Blend in flour and seasonings. Gradually add milk; cook, stirring constantly until thickened. Add 1 1/2 cups cheese. Stir until melted. Toss potatoes in cheese sauce. Pour into 2 quart casserole, reserving 1 cup potato slices. Arrange ham and remaining slices on top of casserole. Bake at 350 degrees for 30 minutes. Top with remaining cheese and serve.