This is deliciously simple to make and what I can only describe as gloriously decadent to eat. By no means a canonical way of making pie, but I love the flaky buttery puff pastry crust with the spiced pumpkin filling and the cloud-like melted marshmallows on top. My only recommendation is that this is a dish that really is best eaten warm; so if you want to make it in advance, I would suggest par-baking the pastry shell, then setting it to one side. Have your pumpkin filling and chunks of marshmallows ready to go, then fill the pie case, top it with the marshmallows and pop in the oven when you're ready to eat.
1 x 320g packet of ready rolled puff pastry
425g pumpkin purée
3 heaped tbsp icing sugar
3/4 tsp ground cinnamon
250g vanilla marshmallows, torn or chopped into chunks
Heat the oven too 200˚C. Drape the pastry over a 9" fluted tart tin with a removable bottom, then gently press the pastry down into the ridges of the tart tin and trim away any excess pastry. Use a fork to prick the bottom all over, then cover with a sheet of baking paper, fill with baking beans and set in the oven for 10-15 mins until the pastry turns lightly golden and the bottom feels dry to touch.
Meanwhile, combine the pumpkin purée, icing sugar and spice together in a small mixing bowl. Beat well with a wooden spoon so you have a smooth filling.
Remove the baking paper and baking beans from the tart case, and fill the pastry with a thick layer of the sweetened pumpkin purée, then arrange the chunks of marshmallow over the top so the entire surface is covered. Set the pie back in the oven for a further 10-12 minutes, until warmed through and the marshmallow topping is melted and burnished. Eat while still warm.