Split Pea and Ham Hock Soup

Put the ham hock in a large heavy pan and pour over the 2.5 litres of cold water, which should cover it by a couple of centimetres.

Bring it up slowly over about 20 minutes, to the point where the first lazy bubbles break the surface.

Skim the grey foam off with a ladle as it gathers, and keep skimming until the surface stays clear.

Hold it at a bare simmer, where one bubble breaks somewhere every second or two, and cook with the lid ajar for 1.5-2 hours, until the meat has shrunk back from the bone and gives under a fork.

Warm the oil in a frying pan over medium-low heat while the hock simmers.

Cook the onion, carrots and celery for 12-15 minutes, stirring now and then, until they are soft and translucent with barely any colour on them.

Stir in the garlic and cook for 1 minute, until it smells sweet.

Lift the hock onto a plate and leave it until it is cool enough to handle.

Tip the split peas into the ham broth with the softened vegetables, the bay leaves and the thyme.

Skip the overnight soak. Split peas are skinned and split along their seam, so they take up water and fall apart inside an hour where whole dried peas would still be rattling around the pan.

Keep the cider vinegar back until the end. Acid firms the skins of a pulse and holds them there, and peas simmered in a sour broth stay gritty however long you give them.

Bring it back to a simmer and cook uncovered for 45-60 minutes.

Stir every 10 minutes with a wooden spoon, scraping right across the base of the pan. Split peas sink as they soften and they catch and scorch without warning, and burnt pea runs through the whole pot with nothing to hide behind.

Add a ladle of hot water whenever the surface stops moving and the pan sounds thick under the spoon.

Stop when the peas have lost their shape entirely and the soup drops off a spoon in a soft mass rather than running off it.

Pull the skin and fat off the hock and discard them along with the bone.

Shred the meat into large pieces with two forks, feeling for small bones as you go.

Stir the meat back into the pan.

Fish out the bay leaves and the thyme stalks.

Loosen with hot water to the thickness you want, remembering that it sets thicker in the bowl and thicker again overnight.

Stir in the cider vinegar off the heat, which lifts a pot that otherwise tastes heavy and one-note.

Season with the ground peppercorns.

Taste before you reach for the salt. A smoked hock can carry the whole pot on its own and no two are salted alike, which is the reason nothing is seasoned earlier.

Scatter the parsley over the bowls as you serve.

Spread whatever is left into shallow containers rather than leaving it to cool in the deep pan, where three litres of soup holds its heat for hours.

Refrigerate it within two hours of the pan coming off the heat and eat it within three days.

Reheat it to a full simmer, loosening with water, and expect it to have set almost solid in the fridge.