Lemongrass is an Asian aromatic herb with long, pale green leaves on a scallion-like base. If you can, buy it when it's pale green and plump rather than straw-coloured and dry. Lemongrass is quite woody, and so, in soup, it is usually used for flavouring but not eaten. It's best in that situation to whack the lemongrass with a pestle or the back of a knife once or twice to release the aromatic oils. Don't pulverize it, just bruise it. If you're using it in salad, you'll need to mince it very very finely indeed.
Something else about lemongrass: don't buy it dried unless you absolutely have to. Like most aromatics, for example lime leaves, it becomes rather flabby and tasteless when dried. Much better to buy it fresh if at all possible.
Hit the motherlode? Suddenly found a good supply of lemongrass that might not last forever? Don't despair! Lemongrass freezes well. | 
