Use walnuts whose shells have not begun to form. Prick well with a silver fork; if the shell can be felt, do not use the walnut. The shell begins to form opposite the stalk, about
Cover with a brine (
Drain, and spread in a single layer on dishes, leaving them exposed to the air, preferably in sunshine, until they blacken (1–2 days). Pack into jars and cover with hot spiced vinegar. Tie down when cold and leave for at least a month before using.