Firstly, make the broth. In a large saucepan add the vegetable stock, mushroom stalks, lemon grass, ginger, basil stalks, star anise and cinnamon. Bring to a simmer.
Cook the shallots and garlic in a dry pan until nicely charred, add to the stock. Leave to simmer for about 15 minutes. Strain to leave just the liquid, season with soy sauce and rice wine vinegar and leave to one side.
Whilst the stock is simmering. Cook the finely sliced shallots in the sunflower oil until crispy, drain onto kitchen roll.
Place a pan of water onto boil. Cook the green beans for 5 minutes, add the mushrooms and bok choy, cook for 1 minute and drain.
Divide the mushrooms, green beans, bok choy and noodles between bowls. Pour in the broth and top with spring onions, chilli and basil leaves. Serve the crispy shallots on the side.