This is an excerpt from Le Viandier de Taillevent
(France, ca. 1380 - James Prescott, trans.)
The original source can be found at
James Prescott's website
Russet soup. Take whatever meat you wish, and fry it lightly in lard with leafy parsley and onions sliced into rounds. Take bread and [chicken] livers, sieve with beef broth and wine, and boil with your meat. Grind ginger, cassia, cloves, grains_of_paradise and cassia flowers, and steep in verjuice. It should be red.
Other versions of this recipe:
Russet Soup is made like George Soup above (Le Menagier de Paris)