Peel and score cucumbers. Slice one-quarter of a cucumber into paper-thin slices and set aside. Seed and roughly chop the remaining cucumbers.

Melt the butter and cook the onions or shallots until wilted, for 2 to 3 minutes; add the chopped cucumbers, broth, vinegar, and 1/3 cup of the dill. Bring the broth to a boil, and whisk in the farina. Simmer uncovered until the farina is very soft, about 20 minutes. Puree.

Before serving, reheat the broth, thinning, if necessary, with a bit more broth or water, and correcting the seasonings. Whisk in one-half of the sour cream or creme fraiche. Garnish with cucumber slices and the remianing dill. Serve the remaining sour cream or creme fraiche on the side to add to the soup, or add a spoonful with the garnish.

For a cold version, chill, and just before serving, whisk in chilled sour cream or creme fraiche, garnishing as above.

potato for the farina for a cucumber vichyssoise.

Add 1/2 cup chopped watercress, or substitute 1 cup watercress for the dill."