Peel the potatoes then slice them thinly about one-eight-inch (3mm) thick. Rinse under cold water to remove any excess starch. Use a little of the butter to grease a shallow oven-proof dish. Gently melt the remaining butter in a pan (do not allow to boil).
Place a layer of potato slices into the dish, drizzle a little butter over them and add a little salt and freshly-ground pepper. Continue this process, creating other layers then cover the dish (aluminium foil will do if you don't have a lid) and cook in a preheated oven at Mk 6 - 400ºF - 200ºC for about one hour until they are golden brown. Sprinkle with a little chopped parsley and serve as a delicious accompaniment for almost any meal.