Peel potatoes, cut into quarters, and boil until done (tender). Drain off water and let dry (if possible in open warm oven). Mash well, add butter, salt and pepper mixing well over a low fire, stirring until smooth. A double boiler is recommended. Remove from fire, add egg yolk and mix well for about five minutes (if possible in warm water to retain heat). Serve hot. Serves 4 to 6. |