500g/1lb 2oz cavolo nero or other kale or dark leafy greens, leaves pulled from stalks and torn into small pieces
1 large floury potato, such as Rooster, peeled and cut into 1cm/陆in cubes
500g/1lb 2oz giant fusilli (fusilloni)
3 tbsp extra virgin olive oil, plus extra to serve
salt
60g/2录oz unsalted butter
150g/5陆oz 鈥檔duja (see Recipe Tip)