Preheat the oven to 375°F (190°C).
In a small bowl, combine the olive oil, minced garlic, garlic powder, Italian herbs, and sea salt to make a paste.
Place the boneless leg of lamb on a roasting rack in a roasting pan.
Rub the garlic-herb paste all over the surface of the lamb, making sure to coat it evenly.
Roast the lamb in the preheated oven for about 25-30 minutes per pound for medium-rare, or until the internal temperature reaches 135°F (57°C) on a meat thermometer. For medium, roast the lamb for 30-35 minutes per pound, or until the internal temperature reaches 145°F (63°C).
Once the lamb is done, remove it from the oven and let it rest for about 15 minutes before carving. This allows the juices to redistribute and ensures that the meat is tender and juicy.
Carve the lamb into thin slices and serve with your favorite sides, such as roasted vegetables, mashed potatoes, or a green salad.