In a large saucepan add in the olive oil, minced garlic and sliced leeks and cook on a low heat for about 8-10 minutes until they are golden and caramelised. While they are cooking add in cracked pepper and salt. Tip- Stir the leeks so that they don't burn. (This is the step that really adds the flavour to the soup)
Add in the chicken stock, zucchini, celery, 2 of the sliced spring onions and simmer on a moderate heat until the zucchinis are tender.
Add in the chopped cooked chicken and boil for another 2 minutes
Add in the rice noodles and reduce the heat to low and simmer for 2 minutes until the noodles are soft. Sprinkle through the remaining spring onions and serve.