Rub lamb liberally with olive oil and season all sides of the lamb with rosemary salt.
Form leg of lamb into an even cylinder and tie every 2 inches with butchers’ twine.
Slide spit through center of lamb and clamp both ends with rotisserie forks.
Place lamb on rotisserie, set to high heat. Add a drip pan under the lamb to catch drippings. Allow to cook for 40 minutes or until internal temperature reaches 130°F.
Remove from rotisserie and allow to rest for 10 minutes before slicing.