Fry the onion in olive oil until softened, then add the garlic and cook for another minute. Then add the cooked beans, the parmesan rind, and half a cup of water. Stir over moderate heat for 15 minutes or so, until the beans are breaking down and the flavour of the parmesan rind has permeated the mixture. Remove the parmesan rind, season the beans with salt and pepper, and then wizz it up in a food processor to a coarse paste.

Toast the ciabatta slices lightly in the oven, then remove and rub with the cut side of half a clove of garlic. Spread on some of the bean mixture, then drizzle a little bit of good olive oil over. Top with some shaved parmesan and a leaf of rocket. Serve at once.

Of course, it didn't turn out exactly this way - I forgot about the ciabatta and burnt them, so ended up using untoasted bread, and there was no rocket to be had anywhere in New Farm that night, damn it, but this is the Platonic ideal of what I ended up making.