Add the carrot juice to the cooker and stir to release any caramelized bits stuck to the pot. Return the cooker to medium heat, uncovered, and rewarm the contents. Transfer the contents of the cooker and the remaining 2 tablespoons of butter to a blender and puree until smooth. Season the soup with pepper and pour into bowls. Garnish with the ginger, tarragon and caraway seeds and serve.