Preheat the oven to 200°C, fan 180°C, gas mark 6. Roll out the pastry and use to line a deep 20x30cm loose-bottomed tart tin, or a 23cm round tin.
Prick the base and line with greaseproof paper and baking beans. Sit the tin on a baking sheet and bake for 15 minutes, then remove the beans and paaper and return to the oven for a further 5-10 minutes until pale golden.
Lower the oven to 180°C, fan 160°C, gas mark 4.
Steam the Cavolo nero leaves for 4 minutes until tender. Cool and drain well then pat dry with kitchen paper.
Arrange the Cavolo nero and pancetta pieces on top of the pastry, leaving a border of about 1.5cm.
Beat together the milk, double cream and eggs until well blended. Stir in the cheese and some freshly ground black pepper, then pour onto the Cavolo nero and pancetta.
Bake for 25 minutes until just set. Leave to cool for 10 minutes, then cut into slices and serve whilst still warm.
*All information included in this recipe has been provided by Produce World.