Place the halved garlic bulbs into the bottom of the roasting tray and add the leg of lamb on top. Rub the garlic, rosemary and oil mixture all over the leg and then season with the salt and ground black pepper.
Place the roasting tray into the oven and roast for 25 minutes then reduce the heat to 200C/400F/Gas Mark 4 for 60 minutes.
After 50 minutes check the temperature at the thickest part without being near the bone. You are looking for 52 – 54C/126F for a perfect medium rare. If the temperature has not reached the mark then put back in and check in another 10 minutes.
When cooked fully, remove from the oven and transfer to a prewarmed plate and cover with aluminium foil. It will keep its warmth for up to an hour.
To make the gravy, we use the contents of the pan. Its full of juicy goodness and flavour from the lamb. Place the roasting tray on the hob and gently tilt. The oil will float on top and can be spooned away but do leave some. The spooned oil should be kept for other dishes to fry in.
Turn the hob on to a medium heat under the pan and when the juices are bubbling, add the flour and stir thoroughly.
4 tbsp all purpose flour
Add half of the beef stock to the tray and stir to help dissolve the flour. The bulbs of garlic are lovely and soft and should be squashed to release all of their flavour into the gravy.
475 ml beef stock
Finally add the remaining half o the stock and stir to make sure everything is mixed. Taste and add seasoning if required.
Once the gravy has thickened, remove form the stove as it will continue to thicken even when off the heat.
Pass the gravy through a sieve to remove the garlic skin etc and pour into a serving jug.
Serve with vegetables and enjoy.
Notes
Note 1: Remove the leaves from the rosemary sprigs and finely chop them.