Wash the peas well and then cover with boiling water (leave enough room for the peas to double in size) and leave them to soak overnight.
Rinse them well and then cover them with cold water in a large pan. Bring them to the boil and boil them hard for 10 minutes and then simmer them for 1-2 hours (until they're tender. Serve hot, preferably in a polystyrene cup (that's the way they do it on the flag market!) with vinegar.
http://parchedpeas.tripod.com/id7.html
Parched peas are a Preston delicacy, made from steeping and then boiling up black peas, and adding vinegar.
http://www.mycookbook.uklinux.net/article.php? sid=227
They are Maple Peas and yes you soaked them and boiled them and then served them with vinegar.
You can steam or boil 'til soft then drain and toss them in a little butter and salt. Lay them out in a roasting pan and put in a warm oven 'til dry.