From "The New York Times Cook Book," Craig Claiborne. Harper and Row, 1990. Put the corned beef in a kettle and add water to cover to a depth of about 5 cm. Bring to a boil and let simmer uncovered 1 hour. Cover closely and continue cooking 3 hours. Meanwhile, put the potatoes in a saucepan and add cold water to cover and salt. Cook until almost tender but relatively firm, 20-30 minutes. The potatoes must not be overcooked or they will not cube properly. Drain and let cool. Peel the potatoes and cut them into very small dice. There should be about 3.5 cups. When the corned beef is cooked, remove and let cool. Heat the butter in a skillet and add the onions and green pepper. Cook, stirring, until wilted. Trim away and discard the fat from the corned beef. Cut the corned beef into very thin slices and cut the slices into very small cubes. There should be about 5 cups. Put the cubed meat into a mixing bowl and add the potatoes and onion mixture. Add the egg and egg yolk, Worcestershire, salt and pepper and blend thoroughly with the fingers. Press down with the fingers to make the mass compact. Cover with clear plastic wrap and refrigerate overnight. Shape the mixture into 8 portions of more or less equal size. (Or, if you prefer, heat butter or oil in a nonstick skillet and cover the bottom with hash.) Flatten each portion into patties. Heat 1 teaspoon of butter or oil for each patty to be cooked. Cook 2 or 3 minutes on one side, or until brown. Turn the patty and cook 2 or 3 minutes on the other side, or until brown. Serve if desired, with a poached egg atop each patty.