Place the squash in a roasting tray, skin side down. Drizzle over the olive oil and sprinkle on the fennel, chilli, oregano, salt and pepper. Rub this mixture into the squash. Roast in a hot oven (abot 200C) for 20-30 minutes or until the squash is cooked (see Cook’s tip).
Once cooked, scrape the flesh into a bowl and discard the skin. Mash the flesh with a fork and add the nutmeg and parmesan. Taste and adjust seasoning if necessary. If the mixture is quite wet and sloppy you will have to place it in a sieve over a bowl to drain off excess water.
Make the pasta by putting the flour and eggs into a food processor and whizzing until it starts to come together. Tip onto a worktop and knead for about 5 minutes until you have a shiny dough. Roll into a sausage shape and wrap in cling film. Chill for half and hour. Roll out using a pasta machine.
Make the ravioli by placing small teaspoons of the squash mixture along a length of rolled out pasta, leaving 3-4cm between each spoonful. Using your finger dipped in water, moisten along and between the spoonfuls of filling. Place another sheet of pasta on top and gently press the pasta around the filling, trying to squeeze out any air pockets. Cut around each one to make the ravioli using a knife or fluted cutter .
Cook the ravioli in a large pan of gently boiling salted water for 2-3 minutes. Drain and transfer to a warmed serving plate. To make the sage butter heat the butter in a frying pan with the sage leaves and let it bubble until it turns foamy and then nutty brown. Pour straight onto the ravioli and serve at once.