Ask the butcher to remove the rind and ribs from the belly - but keep them. Cut the belly and fat into roughly 5cm chunks. Place in a very large pot (or use two pots) with the bones and the piece of rind. Add the salt and pepper and enough water to cover. Bring just to the boil, then reduce the heat and simmer for about 3 1/2 hours, topping up with water as necessary to just keep it all covered. When the meat is very soft and falls apart easily, strain through a colander, collecting all the juice and fat that runs off. Return this to the pan and boil to reduce - you should be left with quite a lot of liquid fat, and just a little of the juice, which should now be a rich brown colour.
While this is happening, squash and shred the meat and solid pieces of fat by hand (rubber gloves are good for this), transferring to a large bowl as you do. Discard any bones, cartilage and rind as you go, but all the rest is edible - and the fat is essential.
Add all the liquid fat and juices to the meat, and taste for seasoning. It should taste too salty, as the flavours will be dulled when cold.
Transfer the mix to terrines or jars, and refrigerate overnight - though it will improve in flavour if you leave it for 3 or 4 days.
Remove from the fridge an hour or so before you want to eat it, and serve with crusty bread and pickled cucumbers.
«There is a lot of fat in this recipe - it's what makes rillettes special, so don't be scared of it. You could add lots of thyme and whole cloves of garlic at the start of cooking if you like. »