This was a really successful variation on our favorite lamb pizza. I topped it with the usual mix of ground lamb and sweet onions, flavored with cinnamon and tamarind, but then added butter-soft, long-cooked broccoli rabe. A recent issue of Saveur had a feature on vegetables cooked until very soft and sweet, and it occurred to me that bitter greens done this way would be a fantastic pizza topping, especially paired with the richness of lamb. I added mozzarella as well, but it would have been equally good with feta or no cheese at all.