The Innsbruck MS can get very playful at times:
64 If you wish to make a hollow roast (holpraten) of meat, chop the meat small and break eggs into it. Salt it and season it and add a little flour. Take a spit that is as large as a rolling pin (welg holtz). Make it pointy, but leave it thick in the middle. Wrap the meat around it and roast it (basting) with fat, and take it off once it turns hard. And if you wish to fill it, use raisins and figs and almonds, or birds in a ziseindel sauce, or fish and bread. Roast it again/more (paz) on a griddle and do not burn it.
This is an interesting recipe. There are other references to Hohlbraten and the idea of filling something into the hole left by the spit – often scrambled eggs – but here, the principle is exploited to the full. It really is more like a Baumstriezel or kurtosh kolach made of meat, cooked on a deliberately large wooden centre. That tradition, too, already existed, so the inspiration may have come from there. I am not entirely sure how hard this would be to get right, but I think I would like to try it just to see what happens.
The Innsbrucker Rezeptbuch is a manuscript recipe collection from a South German/Austrian context. It dates to the mid-fifteenth century and survives as part of a set of medical and culinary texts bound together. The editor Doris Aichholzer published it together with two related manuscripts and drew attention to the less elaborate, more practical recipes. The manuscript is of unknown provenance, but has been owned by the Habsburg emperors since at least the early sixteenth century. It is now held at the Nationalbibliothek in Vienna. An edition, German translation and commentary can be found in Doris Aichholzer: Wildu machen ayn guet essen… Drei mittelhochdeutsche Kochbücher, Peter Lang Verlag Berne et al. 1999