A few drops of lemon-juice. Salt and pepper. One and a half ounces of butter.
Remove all the inside from a large freshly baked potato, and rub it through a wire sieve. Carefully mix into it the beaten yolks of the eggs, the lemon-juice, salt and pepper. Just before cooking, stir in very lightly the stiffly whipped whites of the eggs.
Put the butter into a clean omelet pan, and when quite hot, pour in the mixture. Fry it gently till a pale brown underneath, then hold the pan before a hot fire till the top is brown also. Turn it out on to a piece of paper, sprinkle over it a little chopped parsley, and fold it over like an envelope.
Serve it on a fancy paper on a hot dish. Cost, 5d.