Hot and Sour Soup

A recipe my mom collected from the internet, and now stored here for safekeeping.

Ingredients: (mom's modifications are listed in parentheses)
2 quarts chicken stock (mushroom broth)
2 oz dried mushrooms
1 inch fresh ginger, grated
1 tbs red chili paste
1/2 cup canned bamboo shoots
1/2 cup canned water chestnuts, chopped
1/4 lb pork, sliced thin
1/4 cup soy sauce
1/4 cup rice vinegar
1 ts salt
1 ts pepper
1/2 ts sugar
1/4 cup water
1 egg, beaten
3 tbs oil
green onions, chopped for garnish

Directions:
-reconstitute mushrooms in water according to package directions
-heat oil in wok/pot
-add ginger, chili paste, pork; cook for about 2 minutes
-add bamboo shoots, water chestnuts, mushrooms; cook about 1 minute
-in bowl, combine vinegar, soy sauce, salt, pepper, sugar
-pour into wok
-add chicken stock (or broth from reconstituting mushrooms), bring to boil and simmer for 15 minutes
-add water
-stir soup in one direction to make current, then add egg until feathery
-garnish soup with green onions