This section is from the book "Mrs. Rorer's Vegetable Cookery And Meat Substitutes", by Sarah Tyson Rorer. Also available from Amazon: Mrs. Rorer's Vegetable Cookery And Meat Substitutes.......
Bake as many potatoes as you have persons to serve and allow one egg for each potato. When the potatoes are done, cut a slice from the side of each, scoop out a portion of the potato, leaving a wall half an inch thick. Put the scooped out portion through a potato press, add sufficient hot milk to make it as soft as mashed potatoes; beat until light, add a palatable seasoning of salt and pepper and turn the mixture into the pastry bag. Break one egg into each potato, dust it lightly with salt and pepper, and press the potato from the pastry bag, through a star tube, around the edge of the baked potato, forming a border, leaving the yolk of the egg slightly exposed. Stand these in a baking pan and bake until the eggs are set. Serve plain, or put a tablespoonful of white sauce in the centre of each and garnish with a sprinkling of chopped parsley.