Warm Cucumber Sauce

Tomorrow this will sauce a salmon fillet, smoked salmon & horseradish gnocchi and buttered pumpernickel crumbs. It would also make an interesting soup, perhaps garnished with some cold- smoked salmon roe. All of the flavors - the onion, cucumber, dill, white pepper, butter and lemon are subtle, but entirely familiar. Because you strain the soup through the dill, there are no green specks at all; you're simply left with a hint of its scent. This would be a fun guess-what's-in-it candidate.

2 large spanish onions, sliced thin

1/4 lb butter

3 Tbsp plus 1 tsp salt

6 english cucumbers, peeled and rough chopped

1/4 cup lemon juice

2 qts water

1/2 tsp white pepper

1 bunch dill, rough chopped

- sweat the onions in the butter with the salt over low heat until softened, stirring often and being careful not to brown

- add the cucumber and toss to coat; continue to sweat 5 minutes

- add the lemon juice and cook 2 minutes

- add the water and pepper, bring to boil and simmer 15 minutes

- remove to blender and puree thoroughly

- put chopped dill in mesh chinois; strain cucumber puree through chinois, pressing on the dill with a spoon or ladle for maximum extraction