Wash and dry lettuce and arrange
decoratively with the watercress on a serving plate. Bring wine to the boil in medium
saucepan, add spring onions and 1/2 cup water. Add mussels, cook until shells
open. Remove from saucepan, reserving
liquid. Remove top shell from each mussel
and place mussels on the lettuce and watercress bed. Mix 4 tbsp of the reserved liquid
with walnut oil, use to dress the salad. Garnish with walnut pieces if
desired.