Egg Drop Soup

This is a recipe I adapted from Susanna (and her mom). The fun part is creating the strands of egg in the soup.
8 c chicken broth
½ c green peas
½ c Chinese black mushrooms (otherwise known as shitakes)
150g silken tofu
1 egg
2 stalks of green onion, thinly sliced for garnish
Heat chicken broth to a rolling boil. While you wait, slice the mushrooms. Add the mushrooms to the broth when the broth is heated through. Then add the green peas. Chop the tofu into 1 inch cubes (be careful with this because the tofu will be quite delicate). Add that to the broth and let simmer until the tofu has warmed. If you want a slightly thicker soup, mix two tsp of cornstarch with 2 tbsp water and add to the broth. To create the egg strands, first crack the egg into a small bowl and add 1 tbsp water. Beat thoroughly with a fork or chopsticks. Make sure the chicken broth is still at a rolling boil. With one hand, drizzle a thin stream of the beaten egg into the broth. At the same time with the other hand, slowly make a figure 8 motion with your chopsticks or fork in the soup. Thin, white threads of egg should start appearing. Garnish soup with green onion.