Spoon all but about 4 tbsp turkey fat from
the roasting tin, leaving behind as much
of the turkey juices as possible. Set the tin
over a low heat on the hob and stir the flour
into the juices to make a paste.
Gradually add the turkey stock to the pan,
scraping up any bits stuck to the bottom of
the tin. Once all the stock has been added,
keep stirring until the gravy comes to the
boil, then add the Marsala, if using. Reduce
the heat and simmer gently for 5 mins or
until thickened to your liking.