Pare potatoes and slice very thin (1/8-inch).

Peel onion and slice paper thin.

Separate into rings.

Mince parsley.

In a buttered 10 x 6 x 2-inch baking dish arrange 1/2 of the potatoes.

Layer with onion and parsley.

Cover with remaining potatoes.

Sprinkle each layer with salt and pepper.

Heat together the water and butter until water boils and butter melts and pour over the potatoes.

Bake in a preheated 450 degrees oven until potatoes are tender, 40 minutes.

Top layer of potatoes will be dry.

Serve hot.