• 250 g (½ lb) turtle beans or black kidney beans
• 1 medium onion, peeled and finely chopped
• 1 tablespoon sunflower or olive oil
• 1 tablespoon each ground cumin and paprika
• ¼ teaspoon each cayenne pepper or chilli powder and ground cloves
• 1 tablespoon tomato purée
• 1 litre (1¾ pints) vegetable or chicken stock or water
• salt

Boil the beans for 15 minutes, then rinse and drain and put them in a bowl. Pour fresh boiling water over them and leave for one hour. Rinse and drain them again.

In an enamelled casserole or other pot suitable for both stove top and oven, gently fry the onion in the oil until beginning to brown. Add the spices and cook for 2 to 3 minutes. Stir in the tomato purée, and cook until the mixture thickens and darkens, as the liquid evaporates.

Add the beans and stock, put the lid on and cook until the beans are tender. You can cook this in the oven at 180°C/350°F/gas mark 4, or on a low simmer on the hob. When the beans are soft, add salt to taste.

Allow the beans to cool slightly in their liquid before making a purée of them in a blender or food processor. It is best to do this in two batches, unless you have a large-capacity machine. Alternatively, you can rub the soup through a sieve, or leave it chunky.

If the consistency is too thick for you, gradually add a little more water or stock and appropriate seasoning, until the taste and consistency are as you want them.

I like to serve the soup very hot, pouring it when practically boiling into earthenware soup bowls containing a splash of sherry or rum so that the heat of the soup evaporates most of the alcohol, leaving the flavour behind. I then add to each bowl a very thin slice of lemon, a sprinkling of finely chopped parsley, and perhaps a tablespoonful of soured cream.