A boned roast leg of lamb will be much easier to carve; tie the leg securely so that it cooks evenly. Serve with the pan sauce on the side for a delicious dinner.
Preheat oven to 400 degrees. In a blender, process oil, garlic, 1 tablespoon salt, and 1 teaspoon pepper until smooth and emulsified, scraping down the sides as needed.
Place lamb, fat side up, on a rack set on a roasting pan; spread garlic paste all over lamb. Roast in oven until a meat thermometer inserted into the thickest part of the meat registers 135 degrees for medium rare, about 2 hours.
Transfer lamb to a platter, and discard string; keep warm while you make the Pan Sauce. Slice lamb just before serving.
On a cutting board, chop together 5 garlic cloves, 1/3 cup fresh parsley, and 2 tablespoons of mixed dried herbs, such as rosemary and thyme. Add a pinch of salt. Rub over the lamb before roasting.