This is the Chinese way to make Watercress Soup. It is made with only four ingredients but you will be surprised at how much flavor it has. This recipe was taught to me by my grandmother. You will need two batches of watercress to serve about 6 people. The watercress shrinks quite a bit after cooking.
Fill a large stock pot with 8 cups of water and bring it to a boil. Add the pork ribs and simmer for one minute. Drain the liquid. This step helps remove scum and clean the meat of any odd flavors that might have accumulated since the animal was killed. It is a very popular technique to get a cleaner taste when making Chinese soups.
Refill the stockpot with 10 cups of water, add garlic and salt, and bring to a boil. When the water is boiling, cover with a lid and reduce the heat to the lowest setting. Let it simmer for 1 hour and 30 minutes.
Add the watercress and simmer for another 20 minutes. By now, the meat should be very tender and almost fall apart if you pick at it with chopsticks. Ladle the soup into bowls and enjoy!