Tip the potatoes into a large pan with the stock and a large pinch of salt. Bring to a simmer and cook for 10 mins.

Meanwhile, put the leeks in a bowl and rinse to remove any grit. Add the leeks and chorizo to the pan, season and simmer for another 15-20 mins until the leeks and potatoes are cooked through.

When ready, the potatoes and leeks should be almost falling apart and very tender when pierced with a knife, and the stock should be shimmering with the fat from the chorizo. Season to taste, then remove from the heat and stir through the parsley. Leave to rest for 5 mins, then ladle into deep bowls, grind over a little black pepper, if you like, and serve with thick slices of sourdough.