Preparation Preheat oven to 475°F. Place lamb in large roasting pan. Rub all over with half of minced garlic. Sprinkle with salt and pepper. Place halved heads of garlic around lamb, cut side up. Scatter 1 bunch thyme over and around lamb. Roast lamb 20 minutes. Reduce oven temperature to 350°F. Boil wine in large saucepan for 5 minutes. Pour wine around lamb. Cover and roast until lamb is very tender, about 2 hours 45 minutes longer. (Can be made 1 day ahead. Cool, uncovered, 1 hour. Cover and refrigerate. Rewarm, covered, in 350°F oven for 30 minutes before continuing.) Transfer lamb and heads of garlic to platter. Tent with foil. Using slotted spoon, remove thyme sprigs and garlic skins from pan juices. Place roasting pan over medium-high heat on stovetop. Bring juices to boil. Add butter and remaining minced garlic. Boil until juices thicken slightly, about 12 minutes. Season jus with salt and pepper. Slice lamb; spoon jus over.
Preparation Preheat oven to 475°F. Place lamb in large roasting pan. Rub all over with half of minced garlic. Sprinkle with salt and pepper. Place halved heads of garlic around lamb, cut side up. Scatter 1 bunch thyme over and around lamb. Roast lamb 20 minutes. Reduce oven temperature to 350°F. Boil wine in large saucepan for 5 minutes. Pour wine around lamb. Cover and roast until lamb is very tender, about 2 hours 45 minutes longer. (Can be made 1 day ahead. Cool, uncovered, 1 hour. Cover and refrigerate. Rewarm, covered, in 350°F oven for 30 minutes before continuing.) Transfer lamb and heads of garlic to platter. Tent with foil. Using slotted spoon, remove thyme sprigs and garlic skins from pan juices. Place roasting pan over medium-high heat on stovetop. Bring juices to boil. Add butter and remaining minced garlic. Boil until juices thicken slightly, about 12 minutes. Season jus with salt and pepper. Slice lamb; spoon jus over.