heat the fish broth to boil
split the lemongrass and dip into the broth
pick off the cilantro leaves, finely chop the stock.
finely chop scallions, put into the bowl with cilantro chops and bean sprouts
finely grate the red chile and ginger, put into soup
put shrimp into the soup for 2 min
divide the soup into two, add the sprout-cilantro-scallion mixture
season with salt