Potato Casserole

6 tbsp. butter

1/2 C flour

2 1/2 tsp. salt

1/4 tsp. pepper

2 C milk

4 1/2 C cooked diced potatoes

2 tbsp. parsley

3 tbsp. minced onion or 1 medium onion, diced

1 1/2 C grated sharp Cheddar cheese

Melt butter over a low heat and stir in flour, salt, pepper and milk.  Stir until smooth and very thick.  Add sauce to the potatoes, parsley and onion and mix well.  Place in a greased baking dish.  Sprinkle with grated cheese and bake uncovered for 30 minutes at 400°F.