Heat the oil in a large, heavy pan over medium heat. Add the onion and celery, and cook for 5 mins until beginning to soften. Add the mushrooms and cook for 3 mins until softened. Stir in the garlic, ginger and chicken, and cook for a few minutes until the chicken is browned.

Add the carrots, miso, some salt and pepper, and 1.5 litres water to the pan. Bring to a boil, then reduce the heat, cover and simmer for 20-30 mins, until the chicken is fully cooked.

Remove the chicken from the soup, discard the bones and shred the meat. Add the broccoli and noodles, and cook for 4-5 mins until the noodles are soft. Serve right away, topped with sliced spring onions and red chilli, if you like.