Chicken or Shrimp Salad with Spinach and Roquefort Vinaigrette

This is a very loose adaptation of Helen Corbitt's recipe for Roquefort Mousse with Seafood Salad. That dish is wonderful, but it's really a party dish -- the mousse is more time-consuming than you might wish for a simple supper at home. So I've incorporated the main ingredients of the mousse into a dressing. You could use any kind of seafood instead of or in addition to shrimp, or chicken shredded or cubed (this is a great use for leftover chicken). The idea for the spinach and watercress comes from Craig Claiborne, who suggests this as a bed for seafood salad. I think it seems more like a complete meal with the greens, and they provide a lot of flavor and texture. The dressing is delicious with or without the cream -- obviously the cream will make the dish richer.

Chicken or Shrimp Salad with Spinach and Roquefort Vinaigrette

olive oil
lemon juice
Roquefort cheese, crumbled
tarragon
finely chopped parsley
finely chopped pimiento
finely shopped capers
grated onion
peeled and grated cucumber
salt
pepper
(heavy cream)
Cooked shrimp or shredded or cubed chicken
chopped spinach
watercress

After peeling and grating the cucumber, wrap it in a dish towel or paper towel and squeeze to release moisture. Then spread on paper towel and pat dry.
Combine cheese, cucumber, parsley, pimiento, capers, onion, salt, and pepper and mix well (you can use a food processor for this) until smooth. Add lemon juice and chopped tarragon, then dribble olive oil while stirring vigorously.
Arrange shrimp or chicken on a bed of the spinach and watercress. Top with dressing.