Preheat the oven to 200ºC/400ºF/gas 6. Roll the pastry to the thickness of a pound coin. Get a 22cm loose-bottomed tart tin, line with the pastry and bake blind for 20 minutes. Set aside.
Lay the squash in a baking tray. Sprinkle with the nutmeg, ginger and cinnamon and drizzle with the maple syrup. Cover the tray tightly with a double layer of tinfoil and bake for 45 minutes until soft. Reduce the oven to 180ºC/350ºF/gas 4.
Allow the pieces of squash to cool, then scoop out the flesh. You should have about 600g of cooked squash flesh. Don't forget to scrape out the bits in the tray and the maple syrup. Put in a food processor and whiz until smooth. Transfer to a bowl. Add 2 tablespoons of the sugar and the eggs. Mix well and stir in the cream.
Fill the cooled tart case with the mix and bake for 45 minutes. Meanwhile, wash the stringy bits of squash off the seeds, dry them and lay them flat on a tray. Sprinkle with the remaining sugar and place in the oven with the pie for the last 10 minutes until crispy.
Remove the tart from the oven. Sprinkle with the seeds when cool. Serve with cream or ice cream, if you're feeling naughty.