1. Boil the unpeeled potatoes for 15 minutes, keeping slightly underdone.
2. Peel, cool and cut into 0.5 cm slices.
3. Heat sufficient of the oil to cover the bottom of a heavy frying pan, add a layer of the potatoes, allow to colour underneath, then toss over to colour the other side. Toss again, but not unnecessarily. Clean the pan before Sautéeing the next batch.
4. When all are coloured and fully cooked, toss in the butter in a clean frying pan and season with salt.
5. Serve in a vegetable dish and sprinkle with chopped parsley.