Weigh out exactly 1kg (2¼ lb) of the potato purée and put it in a bowl. Make a well in the centre and add the egg flour, nutmeg, salt and pepper. Work together thoroughly to make a soft, warm dough. Cover with a tea towel. Flour 3 baking trays generously. Break off tennis-ball-sized knobs of the dough and roll out to form long sausages about the thickness of your thumb. Cut into pieces 2.5cm (1in) long.

Take a fork and hold it with the tip of the tines down on the work surface, their outer curve facing upwards. With the tip of a finger, lightly press a piece of the dough against the tines, right at the bottom. In one swift movement roll and flip the dough up and off the fork, so that one side is ridged from the tines, while the other has an indentation from the tip of your finger. You don’t need to take the piece of dough far up the tines – just enough to imprint the ridges on one side only. As you make them, spread the gnocchi out on the floured trays. Once made, cover with a clean tea towel until needed.

Put a large pan of salted water on to boil. Melt the butter in a medium frying pan and add the garlic. Fry gently until it just begins to colour. Add the sun-dried tomatoes, olives and fennel. Stir for about 2 minutes, then draw off the heat.

When the water reaches a rolling boil, drop one- quarter to one-third of the gnocchi into it. When they bob back to the surface, check one to make sure it is cooked. Quickly lift out the rest with a perforated spoon. Place in a warm dish and keep warm while you cook the remaining gnocchi.

Reheat the sauce and then spoon it over the gnocchi. Scatter with shavings of pecorino or Parmesan and serve.