Serve with a little freshly grated Parmesan © Lisa Barber
Serves 4

For the cavolo nero
1 bunch of cavolo nero
80g/3oz unsalted butter
Sea salt and black pepper
For the filling
350g/111/2oz little potatoes (I like Roseval)
140g/5oz unsalted butter
100g/31/2oz freshly grated Parmesan
A small bunch of sage, leaves only, chopped
Sea salt and black pepper

For the pasta (makes about 600g/21oz)
500g/171/2oz flour
4 large eggs
2 yolks
A pinch of salt
A small amount of beaten egg

First, strip the dark leaves from the tough central stalk of the cavolo nero. Place a pan of well-salted water on to boil and plunge the cavolo nero in. Cook for three to four minutes. Drain and set aside.

Place the potatoes in cold, well-salted water and bring to the boil. Turn down to a simmer and cook until they are tender and falling apart. Drain, place in a bowl and add the butter, Parmesan, sage and salt and pepper. Mash together, taste and adjust seasoning if necessary.

For the pasta, ensure all the ingredients are at room temperature. Sieve the flour into a bowl then tip it into a mound on a clean work surface. Make a well in the centre, add the eggs, yolks and salt. Break the eggs up lightly with your fingertips and move your fingers in a circular motion, gradually incorporating the flour until you have enough to start forming a ball. Start working the dough with heel of your hand, folding the dough back on itself, turning it clockwise as you do so. If the dough is dry, wet your hands. Knead for 10 minutes. The dough should feel smooth and springy.

Divide into two balls, wrap each in a damp cloth and leave to rest for at least an hour. Then roll the dough until it is roughly one-inch thick. Place your pasta machine on its thickest setting and feed the dough through, supporting it with one hand and turning the handle with the other. Reduce the setting and feed through again; keep reducing the setting and feeding through as you do so. You should go down three or four settings. Now fold the pasta back on itself. Put the machine back on its thickest setting and repeat the process. The pasta will begin to get longer and finer. Feed it through gently this time, as it can crinkle; dust with flour between each feed.

Now cut the pasta in half, fold each half in two and feed first one then the other through the thickest setting to the finest widthways. Repeat with the second piece. Then repeat this process until you havea pasta that is about 1.5mm thick.

To make the ravioli, lay the first strip of pasta on a floured surface, place little mounds of filling at intervals of about 4cm, brush the sides with beaten egg and lay the second strip on top. Cut into little squares, leaving a border of a couple of centimetres. Boil a large pot of water and cook the ravioli for three minutes, then drain.

Now warm the cavolo nero in the butter, and season with salt and pepper.

Place the ravioli in a bowl and spoon the warm, buttery cavolo on top. Serve with a little freshly grated Parmesan. '