As the name explains, this vegetable is the flower (fa) of garlic chives (gau choi). Identify it in the market as simple, smooth, leafless green stems 8-10 inches long, about as thick as a ballpoint pen refill, with a single conical bud at the top of each.

The smaller, harder and tighter the flower head, the younger the stalk and the more tender it is likely to be. Those with open flowers are considered too old to eat.