Potatoes & Ham Casserole

12 red or gold potatoes cubed
1 stick of butter
1/4c flour
2 cups milk or cream
2 cups cheese
1 cup diced ham
diced green onions
salt & pepper

Boil potatoes until almost tender. Drain potatoes and pour into 9x13 pan.  Melt butter and flour making a rue. Add milk and heat until it becomes thick like a gravy. Pour sauce over potatoes. 
Sprinkle with ham and cheese.  Bake at 350 for 30 minutes.