Chop the artichokes in half and boil them in salted water until cooked, then drain. Remove the hard leaves and purée the artichokes in a food processor. The artichokes must be very young for this soup. The choke will not have developed. Add the purée to the vegetable stock and gently boil for 15 minutes. Pass the soup through a mouli-légume, discard any fibrous matter. Season the soup with salt and freshly ground black pepper, stir in the single cream and bring the soup back to just under boiling point. Serve the soup with thinly sliced toasted French bread, half an artichoke trifolati, and slivers of Parmesan.