From 1922:

Short pastry, ½ lb. to ¾ lb. of raw meat, 1 onion, 1 potato, and parsley. Cooked or raw meat may be used, but it must be free from all fat, skin, and bone. Cut it up into small pieces, then add to it the chopped onion and potato, which should be cut into small pieces or slices. Mix well together, and season, then add the chopped parsley and moisten slightly with gravy or water. Make the pastry and roll out quite thinly, and cut into round or square pieces. Put a spoonful or two of the mixture on each piece, then fold over, and after damping the edges press together. Brush over with milk, and place on a baking-sheet. Bake in a moderate oven. If the meat is not cooked before being put into the pasties allow another 15 minutes to finish cooking. Serve hot.