This is a hearty, spicy soup. This recipe calls for Andouille sausage, a very spicy smoked Louisiana sausage. You can substitute another sausage but be sure to leave time to cook it if it's an uncooked sausage. The soup is good without the sausage, too.

Pick through the dry beans for pebbles. Put the beans in a large pan, adding water several inches deeper than the beans. Put the pan on the stove and bring the water to the boil. Remove from heat and let the beans sit for 1 hour. Pour off the water, and rinse well.

In a frying pan, saute the onion, garlic and celery in oil until vegetables are tender, about 5 minutes.

Return the beans to the pan. Add the chicken stock, sauteed vegetables and ham bone or knuckles of bacon. Bring the beans to the boil, reduce heat and let the beans simmer, uncovered, for 1 hour.

Add cumin, cayenne, oregano, brown sugar, lime juice, red pepper and sherry. Simmer the beans over low heat until they are tender, about 30 minutes longer. Add water or chicken stock if necessary, as the beans must not dry out, and there should be some excess liquid.

Puree the soup in batches in a blender or food processor.

Return the puree to the pan and reheat. Add the sausage and simmer about 10 minutes longer. To serve, top each bowl with a dollop of soured cream and garnish with coriander and spring onions.