1. Take a medium sized saucepan and bring the vegetable stock to a low simmer. Add in the ginger slices and simmer for around 15 minutes or longer. If the stock has reduced, add a small amount of water.
2. As the ginger simmers in the stock, wash and then thinly slice the mushrooms, adding the spinach leaves. After the green onion has been cleaned and sliced very thinly, bring the stock back on a low simmer and then add the mushrooms, before simmering for 1 minute more.
3. After the heat has been turned off, add the green onions and serve the soup hot. You may want to use chopsticks to eat the vegetables with after you have finished the broth.