Whisk the olive oil, wine, 1 tablespoon rosemary leaves, 6 of the garlic cloves, the salt, and the pepper in a bowl and set aside.
Make 12 small incisions in the fatty side of the lamb and insert one of the garlic cloves and some of the fresh rosemary leaves into each slit. I used a small pairing knife and a chopstick to help push it deep into the meat. Put the lamb in a large ziploc bag and pour the marinade in turning to coat. Place in the refrigerator for 6 hours (up to overnight) and remove one hour before you begin to grill to raise the lamb to room temperature.
Remove the lamb from the marinade, draining it well, and pat dry. Stabilize your dome at 225 degrees F and place the lamb on the grate with an indirect heat Double Decker/plate setter underneath. Cook until the meat temperature in the thickest part reaches 130 degrees F. Remove the lamb from the Dome and tent with foil.
Remove the indirect setup. Raise the Dome temperature to 500 degrees or higher as quickly as possible by opening your vents wide. Once you've reached the desired temperature sear the lamb quickly for about a minute on each side. Transfer the lamb to a carving board and let rest for 15 minutes.
Carve the lamb in thin slices and serve immediately.