Handmade soup noodles as described Waldorf Astoria Maitre D’Hotel Oscar Tschirky on pages 34-35 of his 1896 cookbook, Oscar Of The Waldorf. (Original text is in quotes.)
4 egg yolks
2 tbsp. water
¼ tsp. salt
1 egg white
white flour, “sufficient to make a paste”
“Beat well the yolks of four eggs in two tablespoonfuls of water and one salt spoonful (¼ t.) of salt, whip the white of one egg separately, add it to the rest and sift in gradually, stirring at the same time, a sufficient quantity of finely sifted flour to make a stiff paste.
“When quite smooth lay the paste on a floured board and roll out very thinly. Cut the paste into diamond-shaped pieces, put them on a cloth and keep them in a warm place until dry.
“Prepare some nicely flavored clear soup and when it is boiling very fast throw in the pieces of paste and boil for ten to fifteen minutes. Pour the soup in a soup tureen and serve while very hot, with a plate of Parmesan cheese.”