Heat the oven to 180°C.
Place the butternut squash onto a baking tray and roast for approximately 30 minutes until completely tender.
Mash the squash until smooth, then spread onto a plate and leave for 5 minutes to allow excess steam and moisture to escape. Leave to cool slightly.
Place the squash in a bowl and add the egg yolk, Parmesan, ground nutmeg and sea salt.
Gradually add the flour, mixing gently until a soft dough forms. Use only as much flour as needed to bring the dough together.
Transfer to a lightly floured work surface and divide the dough into two.
Roll each piece into a long rope approximately 1.5 cm thick. Cut into 1–2 cm pieces.
Bring a pan of salted water to the boil.
Meanwhile, melt the butter in a pan over medium heat. Add the sage and pine nuts and cook for 2–3 minutes until the pine nuts are golden and the sage is crisp.
Remove the sage and set aside. Reduce to low heat, add the double cream and Parmesan and simmer gently until the sauce starts to thicken.
Add the gnocchi to the boiling water. When they float to the surface, cook for a further 30 seconds.
Lift the gnocchi from the water with a slotted spoon and add directly to the sage cream.
Toss gently until coated, adding a little gnocchi cooking water if the sauce needs loosening.
Serve topped with the crispy sage, pine nuts and cracked black pepper.