Melt butter in a lage frying pan over medium heat. Add the onion, carrot and celery and a good pinch of salt. Saute for 5-6 minutes or until nicely softened but not coloured. Add the garlic and thyme, cook 1 minute.
Increase heat to medium high then add the chicken. Cook, stirring often for 5-6 minutes or until chicken is sealed all over and has turned white. Pour in the wine and allow it to bubble up and reduce by half.
Sprinkle the flour over the mixture and cook, stirring for 1 minute. Gradually pour in the stock, while constantly stirring, until throughly combined. Bring to the boil then stir through the cream.
Reduce heat and simmer for 15 minutes or until the mixture has thickened and chicken is cooked through. Season to taste with salt and ground white pepper. Transfer mixture to a bowl, stir in the parsley and allow to cool completely.