Set a roasted joint of meat aside. Pour the fat and juices from the roasting tin into a jug and allow to settle and separate, then spoon 2 tbsp of the fat back into the roasting tin. Discard the remaining fat, so that you are left with just the pan juices.
Add plain flour and herbs to the roasting tin. Use a wooden spoon to briskly mix it with the fat over a medium heat for a few minutes until you have a smooth brown paste, then stir in the pan juices.
Gradually add beef stock, stirring for 3-4 minutes until thickened. Season, pour in the juices from the resting meat, then strain through a sieve into a jug.