Crush the piece of
celery root in a bowl with a fork; add the
mustard and enough
broth to form a
sauce thick enough to coat a spoon. Pour into a
sauce dish.
Place the tureen on the table before your guests. Remove the
meat and
place it on a cutting board.
Slice thinly.
Place some vermicelli and ceps into 4 serving bowls;
place the sliced
meat on top with a sprinkling of coarse
salt. Serve the
sauce on the side and the remaining hot
broth in bowls.