Preheat oven to 350 degrees.
Pare and slice potatoes thin. Put in buttered baking dish. Sprinkle each layer very lightly with flour, salt, pepper, and butter.
Pour enough milk over the potatoes so it can just be seen through the top layer.
Bake at 350 degrees until potatoes are tender – about 45 minutes to 1 hour.
Potatoes can be topped with grated cheese a few minutes before removing from the oven.