From the Kuenstlich und Fuertrefflichs Kochbuch:
23 Frying Kuechlein for Sick People
Take a quarter of a hen that is boiled, the ‘crumb’ (prosem – i.e. the meat?) of it, cut it small. Take plums, remove the stones, and also cut them up small. Take white bread flour (Semelmeel) into it and add egg yolks, and make a dough as though a küchlein dough. Fry it thus.
24 A Porridge (Breylein) for Sick People
Take egg yolks, discard the whites, use four or five yolks, beat (Treybs) well in a pan and add wine into it (but only) so it becomes thick and not too thin from the wine. It will not cook down very thick. You may well add sugar. Boil it, serve it and give it to the sick. It strengthens people. Do not cook it long, otherwise it will curdle.
25 A Good Soup for Sick People
Take an egg and boil it in wine. When it has boiled, pour off the wine, take the egg and take out the yolk. Force it (zwing – mash it?), pour wine on it and make a soup. Thus a person regains flesh. An old man said so who had become thin and lost much weight, but a doctor made him such a soup every morning and he became fat (faist) and gained weight again.
Many recipe collections include dishes specifically for sick people, and these are all fairly typical for the age. Eggs, chicken meat, and wine were all considered strengthening and healthful. In recipe #23, chicken is creativbely combined with plum (most likely dried prunes rather than fresh fruit) into fritters. They are held together with semelmeel which most likely means the bolted white flour used for making semmel loaves, but today refers to grated bread and may possibly already mean that. Recipes #24 and #25 are for egg yolk liaison soups. These are described so often that I suspect the dish was simply fashionable at the time. The second one goes about it in a rather convoluted way, first soft-boiling the egg and extracting the yolk (a common trick used in making krosseier), finally using that yolk to make a soup. To me, that suggests a degree of magical thinking. Someone had success with this method, and now one must be sure to follow it every time to get the same result.
The short Kuenstlichs und Fuertrefflichs Kochbuch was first printed in Augsburg in 1559 and reprinted in Nuremberg in 1560 and subsequently. Despite its brevity, it is interesting especially as it contains many recipes for küchlein, baked or deep-fried confections, that apparently played a significant role in displaying status. We do not know who the famous cook referenced in the title may have been or if he ever existed.