Preheat oven to 400°. Trim fat from an 8-lb. leg of lamb and rub with olive oil. Cut incisions all over lamb with a knife and stuff with lots of sliced peeled garlic cloves and fresh rosemary. Season with salt and pepper. Place in an oiled pan, scatter more garlic on top, and drizzle with olive oil. Roast until lamb begins to brown, about 30 minutes. Reduce heat to 350°, add 2 cups white wine (and some sliced peeled small potatoes, if you like), and cook until the lamb is medium-rare, about 1 hour. Serve with pan juices.