Remove the membrane from the back side of the ribs. Drizzle olive oil over both sides of the ribs and sprinkle rosemary.
In a deep baking dish, mix the potatoes with butter.
Place the rack of ribs directly on the grates of your grill alongside the dish of potatoes. Smoke for 3 hours or until the internal temperature of the lamb reaches 145°F. During the last 20 minutes of smoking, add the asparagus to the potatoes to cook until tender.
Slice the lamb and serve with potatoes and asparagus.