Make small cuts all over lamb and rub with olive oil, cumin, oregano, salt and pepper.
Place lamb in a heavy-¬based roasting dish surrounded by onions, garlic cloves and lemon halves. Place thyme sprigs on top and cover tightly with foil. Place into oven for 3 hours 30 minutes.
Change oven to grill setting for 20 minutes, remove foil and grill until skin crisps up, remove and set aside to rest. Change oven back to 180°C.
Meanwhile, cook pasta according to packet directions.
Place kale on a baking sheet lined with baking paper, toss in oil and sprinkle with salt. Place into oven and roast for 10 minutes or until crisp. Shred meat from lamb and toss with pasta, and kale. Drizzle with pan juices and serve with finely grated parmesan.
Use Tuscan cabbage (cavolo nero) in place of kale if you prefer.
Pecorino makes a great option to parmesan.
Substitute pappardelle for fettuccine or buy fresh lasagne sheets and tear them up instead for a more rustic pasta.