Remove the first 4–5 tough fibrous outer layers of the lemongrass stalk with your fingers to reveal the softer, yellower part of the stalk that you’ll be using. The remaining layers will still be slightly fibrous.
Using a sharp, serrated knife, slice off the bulb (bottom 2 inches/5 cm) and discard.
Now, using the back of a knife, oblong pestle, or rolling pin (or a wine bottle if that’s all you have), smash the bottom 6 inches (15 cm) of the lemongrass stalk to release the essential oils and separate the fibers.
Next, use a sharp knife and finely chop the bottom ⅓ of the stalk.