• 400 g (14 oz) dried cannellini beans, soaked in cold water overnight
• 1 small carrot
• 1 small celery stalk
• 1 small onion
• 3 or 4 sage leaves
• 125 ml (½ cup) olive oil
• 1 garlic clove, lightly crushed with the flat of a knife
• 2 small sprigs of rosemary

Drain the soaked beans and put them in a large saucepan. Cover with cold water and bring to the boil. Remove the scum that rises to the surface with a slotted spoon and lower the heat slightly. Add the whole carrot, celery, onion and sage leaves. Cook for about 1¼ hours, or until the beans are tender. Remove the beans from the heat and remove as much of the carrot, celery, onion and sage bits as you can manage.

Meanwhile, put the olive oil in a saucepan with the garlic, rosemary sprigs and some ground black pepper. Heat until the oil is well flavoured and you can smell the garlic and rosemary, taking care that they don’t burn. Leave to cool.

Drain the beans, keeping the water. Purée the beans and about 125–250 ml (½–1 cup) of the bean water in a blender or with a hand-held mixer directly in the saucepan. You should have a very smooth thick purée that is not too dense. If it seems to be too liquid, put it back over the heat in a saucepan to thicken a bit, stirring all the time. Season to taste and serve warm, drizzled with the flavoured oil.