How do you make soup out of them?

The recipe came from Jane Grigson's "Good Things", and she took it
from Elizabeth David's "Summer Cooking". It is similar to:

www.astray.com/recipes/?show=Walnut%20soup

However, there is considerable confusion in this thread about what
constitutes a green walnut.

Green walnuts for pickling (and schnapps?) must be picked before
the shells start to form, typically in May or early June, and are
between the size of a large olive and a smallish bantam's egg.

The walnuts for soup should be partly ripe, with fully-formed
shells, and their outsides may be solid and green, black and
flaking or rotting, or have come off entirely.

Walnuts for keeping need to be fully ripe and dry; if not, they
will go mouldy remarkably fast; and it is tricky to get them dry
in the UK. If the summer was too dark and cold, they won't have
much oil in and will shrivel in storage. I won't even try to
keep any of mine this year.


Regards,
Nick Maclaren.