Sift the flour, sugar and salt into a warmed bowl. Stir in the yeast, mashed potato, melted butter, the beaten egg and, lastly, enough milk to make a pliable dough. Knead well until silky smooth. (This can be done in a food processor.) Set aside in a warm place for an hour or so until the dough has doubled in size.
Knead again and then cut into about
Deep-fry for 4 minutes or until they are golden brown, turning them over once during cooking. Drain on kitchen paper and cover with icing made by mixing the icing sugar with the coffee granules and boiling water.