2 leaves cavolo nero, stalks removed, cut into 10cm/4in pieces
small bunch fresh chives, finely chopped
1 lemon, juice only
1.25kg/2lb 12oz baking potatoes (such as Catriona or Spunta)
400g/14oz pumpkin (such as Delica), peeled, seeds removed, cut into 1cm/陆in dice
100-150g/3陆-5陆oz plain flour
2 tbsp olive oil, plus extra for frying
salt
75驳/2陆辞锄 butter
530ml/18fl oz double cream
1 free-range egg, beaten