2) In a shallow 8-cup baking dish, arrange each of the potato slices, ham and onions in two layers.
3) In a small saucepan, add the milk, flour, butter or margarine, salt and pepper together.
4) Stir continuously and cook until the sauce is thick and boils for 1 minute.
5) Pour over the layers and bake in the preheated oven for 40 minutes or until bubbly.
9) Garnish with the chopped chives, if desired and serve immediately on individual serving plates.