Add the chickpeas and their liquid, season generously and crush them slightly with a potato masher. Add the stock, pasta and cavolo nero (and the Parmesan rind if you have it) and bring to the boil.
Once bubbling, reduce the heat and cover. Simmer for 30 minutes and stir occasionally, adding extra water if it needs it. It should be creamy, like a thick soup or stew.
Stir in the Parmesan and discard the rind. Taste for seasoning, and serve drizzled with a little extra-virgin olive oil, extra Parmesan and a pinch of red chilli flakes, if you like.