Asparagus crab soup - sup mang tay cua

1. Bring water to a boil and put the pork bones in. remove the scum, then cover and continue to boil the bones for 1 hour.
2. Remove the bones from the stock and discard.
3. Add the salt and the fish sauce to the stock.
4. Heat the oil and add the chopped garlic and shallots; add the crab meat and fry for 5 minutes over high heat.
5. Sprinkle with 1/8 teaspoon of black pepper, stirring constantly, then add the crab meat mixture to the soup and bring to a boil.
6. Add the corn- starch-and-water mixture and stir for a few minutes.
7. Break the egg open and drop it into the actively boiling soup while stirring.
8. Cook, still stirring, for about 2 minutes, then drop in the asparagus, along with the liquid from the can and the rest of the black pepper.
9. Continue to cook until the asparagus is heated through.
10. Sprinkle the coriander and scallion green over the soup before serving.