Heat the oil in a large saucepan and fry the onion over a low heat for 4-5 minutes stirring ocassionally until softened but not coloured.
Add the garlic and fry for a further 2 minutes stirring occasionally. Pour over the stock, 300ml water and bring just to the boil. Stir in the vermicelli and simmer for 5 minutes. Add the shredded chicken and parsley and cook for 2-3 minutes to warm through.
Season to taste and serve with hot crusty bread. To freeze, cool completely and transfer to a freezerproof container. Seal, label and freeze for up to 3 months.
Defrost before reheating thoroughly before serving - you may need to add 100ml extra hot chicken stock while reheating as the noodles and chicken will absorb some of the stock during reheating.