Ladle into bowls, sprinkle with the coriander and serve. This soup bowl can be made up to a day ahead – add the noodles and bok choi just before serving. It is not suitable for freezing.
Place the prepared vegetables and the cubes of beef in a small soup bowl. Place the truffles --cut into large and small slices -- on top, followed by the slices of foie gras, cut into different sizes.