To make the stock, heat the sesame oil in a large saucepan or stockpot over a medium–high heat. Add the onion and cook for 1 minute. Add the spices, garlic, chilli and ginger and fry for a further 2–3 minutes, stirring frequently. Add 2.5 litres of water along with the tamari, miso, coconut sugar and mushrooms. Cover and bring to the boil. Reduce the heat to low and allow to gently simmer for 20 minutes.
Meanwhile, cook the rice noodles as per the packet instructions. Drain and divide among large serving bowls.
Heat the sesame oil in a large frying pan over a high heat. Add the tofu and mushrooms and fry for 5 minutes, or until golden all over. Divide equally among the serving bowls.
Arrange the remaining vegetables in the bowls and top with the fresh herbs and a squeeze of lime juice. Pour the hot stock through a strainer over the bowls. Sprinkle with sesame seeds and serve hot.