1. Prepare the marinade

• In a small bowl, combine minced garlic, rosemary, thyme, parsley, mustard (if using), black pepper, salt, olive oil, and lemon juice.
• Stir well to create a thick herb paste.

2. Prepare the lamb

• Pat the lamb dry with paper towels.
• Make shallow incisions across the surface of the lamb with a sharp knife to allow the marinade to penetrate deeper.
• Rub the herb marinade generously over the entire leg of lamb, working it into the cuts and crevices.

3. Marinate the lamb

• Place the lamb in a large dish or resealable bag and cover tightly.
• Marinate in the refrigerator for at least 2 hours, ideally overnight for deeper flavor.
• Remove from fridge 1 hour before roasting to bring to room temperature.

4. Prepare the roasting pan

• Preheat the oven to 180°C (350°F).
• Place onion and carrot pieces in the bottom of a roasting pan to act as a natural rack and infuse flavor.
• Add 1 cup of water or broth to the pan for added moisture during roasting.

5. Roast the lamb

• Place the marinated lamb on top of the vegetables in the pan.
• Roast uncovered for about 20 minutes per 500g (1.1 lb), or until the internal temperature reaches:
  • 50–52°C (122–125°F) for rare
  • 55–57°C (130–135°F) for medium-rare
  • 60–63°C (140–145°F) for medium
  • 65–70°C (150–158°F) for medium-well
• Use a meat thermometer inserted into the thickest part of the roast to ensure accuracy.

6. Rest the lamb

• Once desired doneness is achieved, remove the lamb from the oven and tent it loosely with foil.
• Let rest for at least 20 minutes before carving. This allows the juices to redistribute for a more tender, flavorful roast.

7. Carve and serve

• Use a sharp carving knife to slice thin or thick portions, depending on preference.
• Serve with pan juices or your choice of sauce, along with your favorite sides.