Prepare your smoker or indirect grill with hickory and cherry and bring it to 220 to 250 degrees F. Add the rosemary springs to the coals and place the lamb, skin side up, in the smoker or between the two piles of coals on the indirect grill. Cook for 30 minutes and then turn the lamb skin-side down; continue smoke-cooking until the lamb is medium-rare, about another 20 minutes per pound. The internal temperature should be 140 degrees F.
