Soak the peas in about 2 1/2 liters of water in a pot for 24 hours.
Cut the leek into rings, dice the celeriac, roughly chop the onion and add to the peas. Roughly dice the pork neck and add the whole bacon as well. Cook over low heat for at least 4 hours (better still 5 hours) until everything is creamy. Remove the bacon rind and possibly the bacon fat. Spice up.