In a bowl, add the shiitake mushrooms and pour over the just boiled water. Let the shiitake mushrooms sit in the water for 20 minutes. They will re-hydrate and plump up.
Heat a large soup pot over medium-high heat and add 2 tbsp of coconut oil.Add in the onion. Fry the onion in the oil, turning it only occasionally, until it is well browned in parts. Add in the ginger and garlic and saute for 2-3 minutes more.
Add in the star anise, cinnamon stick, water, vegetable stock and fish sauce and bring it simmer.
Drain the shiitake mushrooms but reserve the water they were in. Set mushrooms aside.
Add the shiitake water into the simmering broth. Let the broth continue to simmer on low heat for 45-90 minutes. The longer it simmers the better the flavour. Take care not to have it rapidly boiling or the broth will reduce too much.
Now start on the vegetables and rice noodles.
Heat a large saucepan over medium heat and add 2 tbsp coconut oil. Add in the sliced button mushrooms and let them fry until they start to caramelise around the edges.
While the button mushrooms are frying, heat up a large pot of water for the rice noodles
Slice up the shiitake mushrooms that were set aside earlier. Discard their tough stems.
Add the shiitake mushrooms to the pan and saute for 1-2 minutes.
Now, add in the cabbage and carrots and saute for around 10 minutes until they are softened and slightly caramalised. If you need to add more oil, do so.
Once the pot of water boils, add in the rice noodles and cook for around 6 minutes until they are soft. Drain them and rinse with cold water. Set them aside.
Add the chili and shredded greens to the other vegetables in the pan and saute for 2-3 minutes until the greens start to wilt. Remove the pan from the heat.
Remove the broth from the heat and pour it through a sieve to remove the spices and other ingredients. Taste it and add salt to your liking.
To serve: In bowls, divide the vegetables and rice noodles. Ladle over the hot broth.
Garnish with fresh chili, chopped fresh coriander and vietnamese mint and serve with a wedge of lime.