Lina Wachtelborn Meier, The Art of German Cooking and Baking… (1922)
“ The celery is cut into small pieces, and boiled in water until soft, then strained through a hairsieve. The butter is heated with the flour in it and the milk is now added. The boiled and strained celery is added, let come to a boil, stirring constantly. Add enough salt and pepper to suit your taste, stir in the yolks and serve at once. If you leave the soup standing it will get thick. ”
