- Preheat the oven to 200C/fan 180C/gas mark 6. Cut the pumpkin or squash into chunks, deseeding as you go (see tip). Place in a roasting tin and cover tightly with foil. Roast for 45-60 minutes or until tender. Remove from the oven and leave to cool.
- Whilst the pumpkin or squash is roasting make the pastry. Place the flour and icing sugar in a food processor and whizz briefly. Add the butter and whizz again until it resembles bread crumbs. Beat the egg yolk with 2 tbsp of the cold water, add to the processor and pulse until it comes together, adding more water if necessary. Alternatively, combine the flour and sugar in a large bowl. Add the butter and rub in with your fingers, mix the egg yolk with 2 tbsp water add to the flour, then use a round ended knife to mix it in before bringing it together with your hands. Dust the work surface with flour and roll out to around 2mm thick. Use the pastry to line a 23cm fluted tin or ceramic dish. Trim the edges to fit, prick the base and chill for 15 minutes.
- Line the pastry case with baking parchment and baking beans. Cook for 10 minutes before removing the paper and cooking for a further 5 minutes until the pastry is beginning to colour. Reduce the oven temperature to 180C/fan 160C/gas mark 4.
- Whilst cooking the pastry, peel the pumpkin or squash. Weigh it, as you only need around 500g without the skin (save any extra to put into soup or mash and serve as a vegetable). Blend in a processor or push through a sieve to make a puree. Beat in the remaining ingredients. It will be very liquidy.
- Pour the pumpkin mixture into the pastry case and bake for around 40 minutes until set. Cool and chill before serving in slices with a dollop of crème fraiche.
Clean the pumpkin or squash seeds removing any fibrous bits, pat dry them combine with 1 tbsp maple syrup and ½ tsp cinnamon. Roast in the oven for 10 minutes until golden and serve alongside your pie.