Ash key pickle
Ash key or Ashen key pickle is an ancient pickle made from the seeds of Fraxinus excelsior [European Ash or Common Ash] An odd recipe that probably needs very young ash keys to guarantee a tender pickle.
This recipe comes from John Evelyn's study of vegetables, herbs and salads: 'Acetaria, a Discourse of Sallets, 1699' You can download this book from Project Gutenberg, the free on-line book resource, it is also available in Kindle format from here.
Gather them young, and boil them in three or four Waters to extract the Bitterness; and when they feel tender, prepare a Syrup of sharp White-wine vinegar, Sugar, and a little Water. Then boil them on a very quick Fire, and they will become of a green Colour, fit to be potted so soon as cold.