Sorrel

Because of its bitter flavour, sorrel is often combined with other ingredients. It can be eaten raw in salads or cooked in soups, purées and stuffings and goes particularly well with fish and egg dishes. The sourness of this herb also complements most types of fish, especially oily varieties such as salmon and delicate white fish such as lemon sole; it's also a natural ally of shellfish such as crab and lobster. Try adding butter and chopped fresh sorrel to the pan once the fish has been fried, then serve the pan juices drizzled over it. If fish isn't your thing, add sorrel to a roast chicken or Spanish tortilla, or chop it into a simple goats' cheese salad. Blanch the leaves before use if they taste too sharp.
 http://www.thekitchn.com/got-sorrel-10-colorful-spring-recipes-170262, has a nice list of recipes to use sorrel.