In a small saucepan, warmthe chicken stock and whisk in the cornstarch. Add the chopped mushrooms, soy sauce, ground ginger and most of the green onions (set some aside for garnish.) Bring to bubbling and then stir the soup quickly until it is spinning in the saucepan.
Carefully/slowly stream in the beaten eggs into the spinning soup. You might have to give it an extra spin or two while streaming in the eggs. Let cook for another minute until eggs have cooked and 'ribboned' into the soup.
Remove from heat and serve.
This is the perfect side dish or appetizer for Homemade Fried Rice!