We had a deliciou green salad in Diez once.
The chef gave men the recipe for the salad dressing in return for me sending him a cowboy hat later.
He stressed the to oil/acid ratio was most important:
3 T walnut oil
1 T rice wine vinegar
1/2 t honey
1/4 t fine mustard
1/2 T fine chopped watercress
Pinch of flaked salt
He did not shake the dressing to emulsify it.
A light stir to dissolve the honey.
He said the salad dressing ingredients should be able to be tasted separately.
When watercress isn't in season I have used other fine chopped light tasting herbs.