Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   2      cups          dried black beans
   1      medium        onion -- finely diced
   3      tablespoons   butter or oil
   1      small         carrot -- peeled and finely
                        -- diced
   1                    celery stalk -- finely diced
   6      cups          chicken broth
   1                    ham hock
   1      teaspoon      thyme
     1/4  cup           lemon juice
     1/4  cup           dry sherry
                        sour cream
                        chopped fresh dill

Preparation:

THE NIGHT BEFORE, place beans in a bowl, cover with 3 inches of water and soak at least 8 hours or up to 10. Or, for a quick-cook method, place beans in hot water for 1 hour before continuing with the recipe. Combine onion and oil in a 2-quart pot over medium heat on top of the stove and cook, stirring occasionally, for 5 minutes. Add the carrot and celery and cook another 5 minutes. Add the drained beans, stock, ham hock, thyme. Cover, increase heat to high and bring to a boil. Decrease heat to low and cook, covered, for 1 1/2 hours. Place beans and liquid in a food processor or blender and puree until smooth. Pour the puree back into the pot and add lemon juice and sherry. Place a dollop of sour cream in each soup bowl and sprinkle with some chopped fresh dill. Pour the piping hot soup at the table.