Lemongrass

Listen, lemongrass is a grass, and that is the whole story of how to treat it. Take the stalk in your hand — it's stiff, almost woody, nothing like a soft leaf. Give it a knock with the back of a knife and smell your fingers: that's when the lemon smell really jumps out at you, much louder than what you get just holding the stalk as it is. So bruise it, crush it, slice it fine — you'll feel the fibers give way under the blade, and the kitchen will smell like lemon before the pot even boils.

Choose it by feel, not by size. The stalk should be firm, almost hard near the base, the outer leaves tight. Snap a piece — if it's dry and papery, it's old, and the smell will be faint and dusty instead of sharp. Smell the cut end: sharp lemon, a little grassy. No smell, no reason to buy it.

Some people say the green top is useless: just throw it away. No! It's too fibrous to eat, true, but crush it in your hand and smell it — that citrus hit is still there. Toss it into the broth whole, pull it out before serving. Throw the top away, and you throw away a good part of the lemon smell you paid for.