To cook the flour
Heat the butter in a pan. Add the flour and cook over a medium heat, stirring with a whisk. The flour must not take on any colour. Remove the pan from the heat.
Pour the milk, cream and wine into the flour in one go, bring to the boil while stirring. Reduce the heat, simmer over a low heat for approx. 10 mins., stirring occasionally until the sauce is thick and creamy, season.
Bring the stock, wine and salt to the boil. Transfer the sausage meat to a piping bag without a nozzle, carefully squeeze out the meat and cut off into little balls using a knife, allow the balls to slide straight into the simmering liquid, cook for approx. 5 mins. Remove with a slotted spoon, drain.
Bake the vol-au-vents according to the packet instructions, keep warm. Just before serving, mix the meat balls, cream and chives with the sauce, heat through gently. Fill the vol-au-vents with the meat sauce and mushrooms, garnish with parsley.