Grab two springs of rosemary from your bunch and strip the leaves off using your hands. Set one spring aside and finely chop the other bunch.
With a sharp knife make a series of cuts throughout the lamb around 1 inch apart, around 1/2 inch deep. Make sure to get the bottom & sides but mainly focus on the top side.
Once cut all over insert olives, garlic, and leftover whole rosemary leaves into the holes. For best results add one piece per hole.
Cover the lamb all over with oil from the spray bottle, to get an even cover give the lamb a good rub. Combine herbs de Provence, peppercorns, chopped rosemary & salt and sprinkle over the lamb. Be sure to give the seasoning a light pat down to make sure it sticks to the oil.
Set the temperature to 250°F Once your smoker has come to temperature, place half of your wood chips on the coals and your lamb on the grate Remove the lamb from the heat and cover with aluminum foil. Baste every 30 minutes with olive oil. For best results, use a sprig of rosemary for basing.
Smoke for 3-4 hours until the lamb reaches an internal temperature of 150°F. If you prefer medium rare, remove the lamb from the smoker when it reaches 135°F.
Transfer your leg of lamb to a chopping board, cover it, and let it rest for 10 minutes.