This is an excerpt from Du fait de cuisine
(France, 1420 - Elizabeth Cook, trans.)
The original source can be found at
David Friedman's website
32. And opposite the rosy bruet of meat, make a rosy of fish: and to give to understand to him who will make it, let him take almonds in great quantity according to what he is charged with making, and have them blanched very well, washed and cleaned and very well brayed and moistened with white wine. And when they are well brayed take some of the puree of peas according to the quantity which you want to make and put in white wine and verjuice and spices and white ginger, grains of paradise, and a little pepper - and not too much - and strain this. And take the purée of peas according to the quantity of almonds which he has and then strain this into a fair cornue, and then put it to boil in a fair and clean pot or cauldron according to the quantity which he has, and put in a great deal of sugar and salt in moderation - and take care that there is not too much or too little of anything - and then put it to boil. And, this being done, take a good, large, fair, and very clean frying pan and put in very good fair and clear oil and heat very well; and being well heated and boiling, throw in good well cleaned alkanet and cook it and heat it well and strain it cleanly through one side of a strainer into fair dishes, and then put it into your broth in such good manner that the color of the said broth is closer to the color rose than to red. And then arrange your fish on fair serving dishes and the said broth on top; and also scatter the appropriate sugar-spice pellets on top.