• 200 g (7 oz) cavolo nero or Tuscan cabbage, stalks removed
• 70 g (2½ oz) butter
• 1 onion, finely chopped
• 1 garlic clove, finely chopped
• 35 g (1¼ oz/¼ cup) plain (all-purpose) flour
• 115 g (4 oz/½ cup) fresh full-fat ricotta cheese
• 1 large free-range egg yolk
• 50 g (2 oz/½ cup) finely grated parmesan cheese
• 1 teaspoon finely grated lemon zest
• ⅛ teaspoon ground white pepper
• 10 small sage leaves
• shaved parmesan cheese, to serve

Blanch the cavolo nero leaves in a large saucepan of boiling water for 1 minute, or until soft and wilted, then drain and rinse under cold water. Squeeze the leaves to remove the excess liquid and then pat dry with paper towel. Chop the leaves very, very finely (to make it easier to incorporate into the ricotta).

Heat 20 g (¾ oz) of the butter in a frying pan over low heat. Add the onion and garlic and cook for 8-10 minutes, or until soft but not coloured. Stir in the cavolo nero. Transfer the mixture to a large bowl, add the flour and ricotta and mix well. Stir in the egg yolk, grated parmesan and lemon zest and season with the white pepper and a little sea salt.

Using 2 tablespoons, shape the mixture into 16 quenelles or rounded gnocchi and place them on a lightly floured tray. Place the gnocchi in the refrigerator to chill for at least 1 hour.

Bring a large saucepan of salted water to the boil. Add half the gnocchi to the water and cook for about 3 minutes, or until the gnocchi rise to the surface of the water. Using a slotted spoon or a small sieve, scoop the gnocchi out of the water and put them into a warmed pasta bowl. Repeat the process with the remaining gnocchi.

Meanwhile, put the remaining 50 g (1¾ oz) of butter and the sage leaves in a small frying pan and cook over medium heat until the butter has melted and the sage leaves are crisp. Spoon the sage leaves and butter over the gnocchi and garnish with some shaved parmesan.