Preheat the oven to 200 degrees Celsius. Cut the pumpkin (skin on) into chunks approximately three centimetres thick. Add them to a bowl with some oil and salt, mix well and spread evenly over a
baking tray lined with baking paper. Bake for about 30 minutes in the centre of the oven.
Once cooked, press the hot pumpkin with its skin still on through a potato ricer and leave it to cool.
Add the flour, parmesan and egg yolk to the pumpkin puree and season with cinnamon and nutmeg, mix, then knead well until themixture forms a smooth dough.
Then, on a lightly floured surface, roll the dough into a long, thin sausage shape approximately one and a half centimetres in diameter. Cut each roll into pieces about one centimetre long. Roll each piece of dough over the prongs of a fork, using your thumb to create a grooved pattern in the gnocchi. Set the gnocchi to one side on a floured surface until you are ready to cook it. To cook the gnocchi, place them in gently boiling salted water until they rise to the surface. Remove the gnocchi with a slotted spoon and let them dry.
Finally, heat the butter in a frying pan and add the gnocchi along with the sage leaves. Fry everything together for around five minutes.
Serve with parmesan to taste.