Paraphrased from Nigella Lawson's book "Feast". She is such a delight to read! I have a pot simmering on the stove right now and I just had to share. She suggests serving this soup on New Year's Day, so I'm running a little late.
Peel the onion, carrot and garlic and cut the onion and carrot into rough chunks. Put them all, along with the roughly cut up stick of celery into the bowl of a food processor. Blitz till all are finely chopped.
Spoon the oil into a heavy-based wide saucepan and put on medium heat. When warm, add the chopped vegetables from the processor and cook for 5-10 minutes, until soft but not colored.
Add the ground mace-give a good stir and then add the split peas and stir again until their are glossily mixed with the oil-slicked, cooked-down vegetables. Pour over 5 cups stock and add the bay leaves, then bring to a boil. Cover, turn down the heat and cook for about an hour until everything is tender and sludgy, adding more stock as needed. Sometimes the peas seem to thicken too much before they actually cook and need to be watered down. Taste for seasoning once everything's ready.
You can add the frankfurters as you wish. It's probably easiest just to cut them into slices - I tend to add them in chunks of about and inch each - and throw them into the soup warm, but I just put them in the microwave (40 seconds on high is about right for one or two franks) then slice them hot and add them to each person's bowl as they come. Not an elegant soup, I'll admit, but a near-perfect one.