Here is a simple recipe for pickling walnuts. Leaving them in the sun is what gives them the characteristic blackness. Green walnuts are picked in late june or early July, before the shell begins to harden.
Soak the walnuts in the brine for 4–5 days, drain them, and put them in the sun for 2–3 days to dry and blacken. Pack them into jars. Pour boiling pickling vinegar over the walnuts, and distribute the spices, evenly if possible, between the jars. Cover and seal whilst still hot. The pickles should be kept for a month before using in order to be fully mature; they will keep unopened for much longer, about 1–2 years.
© 1995 Frances Bissell. All rights reserved.