Almost all recipe collections have recipes for this kind of dish. Cgm 384 II has two:
For a fürhess, take the lungs and the liver and the innards (westin) of a hare and cut it into cubes (wuirflott). Catch the blood and boil it with that, and add a little broth, wine and vinegar, honey and bacon to it. That way, you will have a good fuirhess.
A fuirhess: Take the lungs and liver and catch the blood of a hare. Chop it small and boil it with the blood, with the venison, with wine and with vinegar, and with good broth. Also chop bacon very small, add it, but let it sweat in a pan (vss gaun in ainer pfannen) beforehand. Pass it through a cloth with toasted rye bread, spice it, and let it boil up.
Fürhess recipes share a few features: They were always made with meat cut up small, and they always involved blood. The most likely origin is in processing small animals. Various ‘fiddly bits’ of meat and a quantity of blood that was not worth making into sausage could be used in such a dish. Some recipes also include onions, apples, raisins, and specific spices.
The two recipes in this collection appear to be for slightly different kinds of fürhess dishes. The first has recognisably cubed pieces of meat and may well be meant to be rather thick. The second is passed through a cloth which, if the meat is included, suggests a nearly liquid consistency. It is hard to say what consistency a fürhess was expected to have. Some recipes specifically mention boiling in liquid and make something more like blood soup while others add the blood to meat in a frying pan, which creates a porridgelike consistency. I prefer the latter, but have no better evidence for it than that.
Bound together with medicinal, veterinary, and magical texts, the culinary recipes of Munich Cgm 384 were partly published in 1865 as “Ein alemannisches Büchlein von guter Speise“. The manuscript dates to the second half of the fifteenth century. My translation follows the edition by Trude Ehlert in Münchner Kochbuchhandschriften aus dem 15. Jahrhundert, Tupperware Deutschland, Frankfurt 1999, which includes the first section of recipes not published earlier.