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
Soringue. Scald or skin the eel, cut it into sections, and fry it lightly in oil with leafy parsley and onions sliced into rounds. Take browned bread, puree of peas or boiled water, and wine (mostly), sieve, and boil with the eel. Take ginger, cassia, cloves, grains_of_paradise and saffron (to give it colour), steep in verjuice, and boil with the eel. Season it with vinegar.
Other versions of this recipe:
If you want to make sarraginee (Enseignements qui enseingnent a apareillier toutes manieres de viandes)
Sorengue (Du fait de cuisine)