Start preparation a day in advance by soaking the chick peas in plenty of cold water to which the bicarbonate of soda has been added. The next day, drain them in a sieve and rinse well under running cold water; place in a saucepan with the stock. Cover, bring slowly to the boil and then simmer gently for 1 1/2 hours.

When the beans have been cooking for about 1 1/4 hours, wash the spinach, drain and cut into thin strips. Chop the peeled onion, garlic and carrot finely with the trimmed and washed celery and fry gently in 3 tbsp olive oil in a large, heavy-bottomed saucepan or flameproof casserole dish for 5 minutes, stirring with a wooden spoon.

Add the flour and stir continuously for 1 minute as it cooks. Add the shredded spinach, stir, draw aside from the heat and add about 8 fl oz (225 ml) of the cooking liquid from the chick peas, beating continuously to prevent lumps forming as the flour thickens the liquid.

Add the contents of this saucepan to the pan containing the cooked chick peas. Cover, and simmer gently for 15 minutes.

Remove from heat and blend or process until smooth. Return to the pot and heat through.