Cut the neck of mutton into pieces two and one half or three inches square. Put them into a saucepan with the butter, and let them brown; stir frequently so they do not burn. When browned add enough water to cover them well, and the onions cut into pieces. Cover closely and let simmer two hours. Then add more water if necessary, some parboiled potatoes cut in two, and a few slices of carrot, salt, and pepper to taste; cover and let cook one hour more. A teaspoonful of Worcestershire sauce is an improvement. The gravy must be quite thick, so too much water must not be used. The potatoes should be very soft, but not broken.