3 All-Purpose Flour
Preheat oven to 400 degrees Fahrenheit.
Lightly spray a 2 quart casserole with vegetable spray.
Arrange a layer of potatoes in casserole, then sprinkle with some of onion, flour, salt and pepper.
Continue to layer until all potatoes, onion, flour, salt and pepper are used.
Dot top with butter, then pour milk over all.
Bake 20 min, then reduce heat to 350 degrees Fahrenheit and bake 50 to 60 min longer or until potatoes are tender.