Peel and slice your Potatoes very thin into a pie dish; between each layer of Potatoes put a little chopped onion (three quarters of an ounce of onion is sufficient for a pound of Potatoes); between each layer sprinkle a little pepper and salt; put in a little water and cut about two ounces of fresh butter into little bits and lay them on the top; cover it close with puff paste. It will take about an hour and a half to bake it.