Step 4: Preparing the filling: making a bechamel sauce
The dripping separated from the roast chicken juices
The roast chicken juices plus (free range) milk / water / stock to make 1L of liquid
60g unbleach plain flour
Salt and pepper and wholegrain mustard for seasoning
Thinly sliced pan seared mushrooms to taste
Finely chopped flat leaf parsley to taste
Put the dripping into a saucepan, mix in the flour until you have a smooth paste. Put the saucepan over a low heat and gently simmer the flour paste for a couple of minutes (this cooks the flour and improves the flavour of the bechamel sauce).
Slowly add the milk stirring continuously until the flour paste is dissolved thoroughly without forming lumps.
Now you can turn the heat up a little, stir until the sauce is really stiff and thick. Make sure you scrape the bottom of the saucepan to prevent the sauce from catching.
Season to taste (easy on the salt if you used salted butter in the pastry).
Add the mushroom and the parsley.