Over a medium heat cook the mushrooms and butter in a heavy based pot. Add the flour and continue cooking for 1 minute. Slowly add the milk or cream, stirring until the mix comes back to boil. Add the cooked chicken, ham and chopped parsley. Check for Salt & Pepper.
Take 4 bowls and line with cling film. Divide the chicken & ham mixture between the 4 bowls and place in a fridge to set.
Once set you are ready to assemble the pies cut 4 smaller discs of puff pastry as bases and 4 larger discs for top. Turn the set chicken & ham mix out and place one on each smaller pastry disc. Brush the edges with the beaten egg before covering with a larger disc of puff pastry. Using a fork, press or crimp the edges together, brush the top with egg wash before cooking for 20 minutes in a hot oven (gas mark 6).
To Serve:Serve warm.