Peel the long potatoes at the last minute. Slice into paper thin rounds 3 mm (⅛ in) thick and about 5 cm (2 in) in diameter. Wipe with a cloth or kitchen paper, put into a dish and season with salt and pepper.
Bring the milk to the boil in a deep heavy saucepan. Put the potatoes in, one round at a time, and bring back to the boil. Cover the pan and cook over a