Preheat the oven to 200°C.
Coat butternut squash pieces in 2 teaspoons of olive oil and season with salt and pepper.
Roast the squash in a tray for 20 minutes until tender.
Toss onion slices in remaining oil and seasoning.
Add onions to the tray and roast for another 10 minutes.
Blend warm vegetables into a smooth purée and let cool for one hour.
Stir in grated cheese and nutmeg into the cooled purée.
Pulse flour and eggs in a food processor to form a dough.
Knead the dough on a floured surface for 10 minutes until smooth.
Divide dough into four portions, wrap in cling film, and chill for 30 minutes.
Roll a dough portion to 1mm thickness and mark 12 circles with an 8.5cm cutter.
Roll out a second sheet of dough to the same size.
Place teaspoons of filling onto marked circles and moisten the edges with water.
Drape the second sheet over the first and press to seal and remove air.
Cut out the ravioli using the cookie cutter and place on a floured tray.
Repeat the process with the remaining dough and filling to make 24 total ravioli.
Fry sage leaves in oil until translucent, then drain on kitchen paper.
Fry sun-dried tomatoes in the same pan for 30 seconds.
Boil ravioli in batches in salted water for a few minutes until cooked.
Drain ravioli and toss with sun-dried tomatoes before serving with sage and extra cheese.