Sour cream Chopped fresh dill 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.