Chervil, a close relative of parsley, is an aromatic, mild-flavored herb with subtle anise flavor. It has bright, lacy green leaves, and alhough it is available both dried and fresh, its delicate flavor is almost completely lost when dried. Chervil's flavor also quickly diminishes when heated, so be sure to add it to your dish near the end of cooking.
Supermarkets package fresh herbs in various ways: loose in small plastic boxes, fastened in bunches with rubber bands, or sometimes still growing in a pot. No matter the packaging, look for herbs with vibrant color and aroma (open up those boxes for a sniff), and avoid those that are limp or yellowing, have black spots, or don't smell totally fresh and appetizing.
Wash chervil only when you're ready to use it, because excess moisture shortens its shelf life in the refrigerator.
To wash herbs, put them in a large bowl of cool water and swish them to release grit. Lift the chervil out of the water with your hands, a sieve, or a skimmer. If you see a lot of grit on the bottom of the bowl, wash it again in a fresh bowl of water. Spin it dry in a salad spinner or gently blot it dry by rolling it up in a clean towel.
A sharp knife is imperative for chopping herbs. A dull one will crush and bruise tender leaves, giving you blackened rather than green results. You can use scissors to snip off small amounts.
The more tender the herb, the closer to cooking time you'll need to chop it. If you chop chervil in advance, cover it with plastic wrap punctured with a few air holes and refrigerate it. You can save leftover chopped herbs for a day or so, but sniff them before using.
To keep this tender herb at its best, remove any rubber bands or fasteners. Because the roots draw the moisture from the leaves, it's important to trim off the root ends and the lower parts of the stems to prevent the tops from wilting. If the roots are large and prominent, you can save them to flavor soups or stocks.