Combine all ingredients in a bowl. Rub over lamb shoulder, set aside for 15 minutes.
Pre heat barbeque smoker to 130°C - 135°C.
Place lamb shoulder in the barbeque and insert a probe in the thickest part of meat. Cook lamb to an internal temperature of 65°C. Using the spritz, spray every 30-60 minutes to ensure meat remains moist.
Remove lamb shoulder and wrap in foil (Texas crutch hold). Place back in barbeque to finish cooking to internal temperature of 95°C. Remove, open foil for 5 minutes to allow steam to escape, and re-wrap in foil and tea towels, place into an esky and rest for 30 minutes
Unwrap the lamb and serve with celery, fennel and apple salad and lemon wedges.
