This is an excerpt from Das Kuchbuch der Sabina Welserin
(Germany, 16th century - V. Armstrong, trans.)
The original source can be found at
David Friedman's website
176 To make a good May cake. Take a pound of raisins, a pound of currants, five small portions of May butter, a handful of hyssop, a handful of ground ivy, some sage, about ten leaves, two times as much mint, a handful of costmary, approximately fifteen eggs and a half pound of sugar; the herbs finely chopped, baked for two hours. The butter must be stirred into the herbs. For the crust, two eggs, which are prepared as for a tart.
Other versions of this recipe:
If you want to make a May cake (Das Kochbuch des Meisters Eberhard)