Here's cooking instruction for :
1. Preheat your oven to 350F (175C).
2. Take the lamb leg out of the refrigerator and let it come to room temperature for about 30 minutes.
3. Meanwhile, prepare any desired seasonings or maride for the lamb leg. You can use a combition of herbs like rosemary, thyme, garlic, and olive oil.
4. Rub the seasonings or maride all over the lamb leg, making sure to coat it evenly.
5. Place the lamb leg on a roasting rack inside a roasting pan, with the bone side down.
6. Place the roasting pan in the preheated oven and cook for about 20 minutes per pound (450 grams) of lamb. For example, if your lamb leg weighs 4 pounds (1.8 kg), you would cook it for approximately 1 hour and 20 minutes.
7. About halfway through the cooking time, baste the lamb leg with the pan juices to keep it moist and flavourful.
8. Use a meat thermometer to check the interl temperature of the lamb leg. For medium-rare, the temperature should reach 135-140F (57-60C), for medium, it should be around 145F (63C), and for well-done, it should reach 160F (71C).
9. Once the desired temperature is reached, remove the lamb leg from the oven and cover it loosely with foil. Let it rest for about 15 minutes to allow the juices to redistribute.
10. After resting, carve the lamb leg into slices and serve hot.
Remember, cooking times may vary depending on the size of the lamb leg and individual ovens, so it's always a good idea to use a meat thermometer to ensure the lamb is cooked to your desired level of doneness. Enjoy your delicious roasted lamb leg!