Preheat the oven to 350°F (175°C).

In a small bowl, mix together garlic, rosemary, thyme, olive oil, salt, pepper, and lemon juice to create a marinade.

Rub the marinade all over the leg of lamb, ensuring it is well coated. Let it marinate for at least 30 minutes or up to overnight in the refrigerator.

Place the marinated leg of lamb in a roasting pan and insert a meat thermometer into the thickest part of the meat, avoiding the bone.

Roast in the preheated oven for about 1.5 to 2 hours, or until the internal temperature reaches 135°F (57°C) for medium-rare.

Remove the lamb from the oven and let it rest for 15-20 minutes before carving.

Slice and serve with your choice of sides.