I mention sorrel because it is not appreciated as much as it should be. It looks a little bit like spinach—not as dark—but tastes distinctly sour as soon as you bite into a leaf. Most people think of it as an herb to be chopped or shredded and then sprinkled into sauces. Truth be told, sorrel has very little of a distinct flavor that would make it useful as an herb, but it does have a sprightly acidity that makes it wonderful when served as a vegetable (it can be combined with spinach) or worked into a soup.
Don’t boil or blanch sorrel as you would spinach or it will just melt away and loose flavor. It is better to put it in a pan with a little butter or reduced cream and just stew it until it “melts,” for a minute or two. Sorrel also makes one of the best possible soups. You can make a soup out of a leek and potato base by simply stirring in sorrel a minute or two before the cooking is completed. The soup should then be pureed and finished with cream, although you don’t need a lot of cream. Another method, used to make the classic potage Germiny, requires good veal or chicken broth. The broth is used to cook the sorrel, the soup is pureed and thickened with egg yolks. It is then finished with cream. Some versions call for chervil. This soup can be served hot or cold. For more about using egg yolks, see crème anglaise, page 000. To make sorrel sauce, deglaze a pan used for sautéing (fish, say), add a little chiffonade (thin strips) of sorrel and heat just long enough for the sorrel to loose its color. Add cream or butter.
I have also encountered sorrel mousse. Make a potage Germiny, add gelatin to it, let it cool (but not set) in the manner of a Bavarian cream and fold it with cream whipped to medium peaks. Put in molds and allow to set. I got this idea from a triple-layer Bavarian cream (the other mousses were chicken and tomato) out of Richard Olney’s The French Menu Cookbook.