When the cooking time is finished, remove the lamb, potatoes and carrots from the roasting tin and leave them to rest for a few minutes while you make the gravy.
Place your roasting tin on the hob, mixing all the juices with a whisk.
Addin the beef or lamb stock cube/ pot and mix again.
Now add the flour and give another good mix.
Finally, slowly pour in a hot pint of water, quarter by quarter, mixing as you pour.
Carve and serve!