Drain the beans, then put them into a large pot or casserole dish with enough fresh water to cover them by one and a half times. This is important: you don’t want so much water that the beans will overcook. Throw in the onion, bay leaf and pork ribs, but don’t add any salt at this stage – it will make the skins separate from the beans.
Partially cover with the lid and cook on a medium heat, so it’s gently bubbling, for 20–25 minutes, then add the potatoes and pancetta.
Add the chorizo and morcilla 10–12 minutes before the end (any longer and the morcilla will break), with enough water to just cover.
Taste, and when the beans are soft, season.
To serve, everything must be hot (except the pickles). Discard the onion and bay leaf and transfer the potatoes, pork ribs, chorizo, pancetta and morcilla to a large plate. Put the piparras on a small plate. Slice the chorizo and morcilla into medallions and chop the pancetta into lardons. Serve everything in the middle of the table: the beans in their pot, the plate of meat and potatoes, and the pickles, with lots of bread to scoop up the juices.