If you find one recipe for something you are convinced can’t possibly be edible, you doubt your interpretation. Once you meet the second and third, though, it is time to reassess your estimate of edibility. These are from the Inntalkochbuch:
<<15>> Von einem hirschen horn, das zeitig ist
Of deer antler that is in season (i.e. young)
Remove the hair, boil it well, and let it cool. Take good wine, sugar or honey, and serve that cold with all things. Item: you can also serve it with onions.
<<16>> Von einem andern gehörn
Of another gehörn (antler)
Take a calf’s head and press it entire, place the horn on it and fasten it with a tack or nail, place it on a platter with boiled venison around it and serve.
<<37>> Von einem hirschen gehörn
For a deer’s antlers
At the time it is fuzzy and soft, take it and clean it thoroughly and singe it over a fire, then cut the upper part into slices, as many as you can get out of it. Take honey and boil it by the fire. Dry leczelten (a kind of gingerbread) by the fire. Take the bone (the hard part of the antler) and chop it, then grind it in a mortar. Then take the honey, wine, gingerbread, and the blood from the antler and pass it through a clean cloth. Boil the antler in this.
At this point, you could still think that Gehörn (in modern German, used exclusively for the antlers of roe deer) might just be a dialect rendering of Gehirn (brain). And then you look at the Königsberg MS and there is this:
[[16]] Wilthu machenn ein Hirßcornn:
If you want to make hartshorn
Take the horn (antlers) when they are soft and boil them and cut them into Scheinenn (strips? slices?) as much as you like or can get of the antler. Take honey and boil the impurities out of it, then take gingerbread and sieve it. The Peiß (usually a marinade or sauce) that you can not get you take and chop finely. Add honey and ground gingerbread and the hart’s blood and pass that through a cloth. Place the antler in it and boil it.
That recipe had me stumped, but it clearly is a corrupted parallel of what we have in the Inntalkochbuch (incidentally, an interesting link between the traditions since the Königsberg MS otherwise closely parallels Cod Pal Germ 551). There is really no doubt that someone was eating antlers. Can you actually do that?
It turns out the answer is yes, sort of. If antlers are harvested at what is called the velvet stage, while they are still growing, a significant part of them consists of cartilage which can be cooked. People in East Asia, where variations in texture are valued in culinary arts more than they are in the West, have been doing it for centuries. In America today, this mainly happens in a corner of the nutritional supplement industry. And it looks like it was also familiar to medieval Germans.
Why would they have done this? I think that we can exclude the idea of necessity as the mother of this invention from the start. Venison was an upper-class food. If you ate deer, you were not short of animal protein. A more convincing source is simply because you could. Cooks took great pride in their ability to turn any part of an animal into palatable dishes (see my essay ‘Offal and the Master Cook’ in the 2016 OSFC Proceedings). Immature antler would have been just the kind of challenge they relished. And of course, we should not disregard the aspect of status: Antlers suitable for eating were only available for a short time, only to those who hunted, and every animal would have yielded only a small quantity. Whoever got them had something rare on their plate, and the symbolic connection between antlers, masculinity, sexuality and power surely was lost on exactly nobody.
Which leaves the question what it tasted like. I don’t know since I have never had immature antler (and barring a miracle, never will, since deer are not hunted at this life stage in Germany any more). I suspect it would not have been a culinary revelation exactly. For one thing, it was prepared with a sweet and spicy sauce. The kind of blood-bound sauce described in the final recipe of the Inntalkochbuch is commonly found in recipes for venison fürhess, a category of dishes that often included organ meats and other ‘fiddly bits’. As with shark fins and swallows’ nests, the rarity of the item probably trumped its taste here.
The Inntalkochbuch is from a monastic library in Bavaria’s Inntal region (the Inn is a tributary of the Danube), dating to the late 15th/early 16th century. It is written in Upper German and strongly reflects local culinary traditions, though some of its recipes are commonplaces found elsewhere.
The Königsberg MS was preserved in the archive of the Teutonic Order in Königsberg (today Kaliningrad) in Baltic East Prussia, though its language suggests that it belongs to a Central or South German background. It is not associated with any name that I am aware of and is dated to the late 15th century purely on the scribal hand. The recipe types match South German sources of that time. It was published in Gollub (Hg.): Aus der Küche der deutschen Ordensritter. in: Prussia 31 (1935) pp. 118-124.