1. Line the flan dish with the pastry circle and place in the refrigerator to rest while the filling is made.
2. Place the pieces of pumpkin, with the skin on but with the seeds removed, into the half size AGA roasting tin with 2 tablespoons of water and cover with foil.
3. Slide the tin onto the third set of runners down in the oven and steam for 45 minutes to 1 hour, or until tender.
4. Scrape the pumpkin flesh into a bowl, discard the skin and mash to a pulp. Add the cinnamon, ginger and nutmeg, mix well. Whisk together the sugar and eggs then whisk in the crème fraîche. Stir in the spiced pumpkin pulp in two lots. Pour into the pastry case.
5. Cook on the floor of the oven for about 35-40 minutes until set.
6. Allow the flan to go cold. Using the melted chocolate, pipe a spider's web on top. Serve cold with whipped cream.
7. Rayburn cooking: Bake on the floor of the main oven at 200°C (400°F), Gas Mark 6 for about 35-40 minutes until set.
8. Conventional cooking: Cover the raw pastry case with foil and tip in baking beans, bake 'blind' for 15 minutes at 200°C (400°F), fan oven 180°C, Gas Mark 6. Remove the foil and beans then pour in the filling. Reduce the oven to 180°C (350°F), fan oven 160°C, Gas Mark 4 and cook for a further 25 minutes until set.
Tip - if you are making your own pastry add half a teaspoon of cinnamon to the mixture.
Recipe from Dawn Roads, home economist at AGA Cookshop