For the cookie shell, Blitz the cookies to fine crumbs in a blender or food processor. Add the melted butter. Stir well so that all the crumbs are coated. Press the crumbs into the prepared pan using the back of a spoon so that they cover the base and come about 1-1/4 in. / 3 cm up the sides in a thin layer.
For the pumpkin Chantilly, Put the pumpkin puree in a heatproof bowl over a saucepan of simmering water and heat for 10 minutes, stirring occasionally. Add the 3 egg yolks, 1/4 cup/ 50 g of the sugar, milk, salt, vanilla bean paste, ginger, nutmeg, cinnamon and melted butter to the bowl, and whisk together. Cook for a further 10 minutes over the saucepan, then remove from the heat. Dissolve the powdered gelatin in the warm water, whisking well. Whisk the dissolved gelatin into the pumpkin mixture, then leave to cool. Whisk the 4 egg whites to stiff peaks and then fold in the remaining 1/4 cup/ 60 g/generous of caster/superfine sugar a little at a time. Gently fold the egg white mixture into the pumpkin mixture, until fully incorporated. Pour into the cookie shell and allow to set in the refrigerator overnight.
For the topping, Heat the sugar in a pan over low heat, until it melts and starts to turn golden. Do not stir the sugar, but swirl the saucepan over the heat from time to time to ensure even cooking. Watch carefully as when the sugar melts it can easily burn. Spread the pecans out on the silicon mat or a greased baking sheet and swirl over the melted sugar in pretty patterns, coating the pecans. Leave to set. These are best made shortly before serving as they become sticky when exposed to the air.
To serve, carefully slide a knife around the edge of the pan to release the cake. Whip the cream to stiff peaks, and arrange it over the top of the pumpkin Chantilly, forming soft peaks. Top with the caramelized pecans, and serve immediately.
Excerpted with permission from: <a href="https://www.amazon.com/gp/product/1849759715/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1849759715&linkCode=as2&tag=craftfocom-20&linkId=9a881e6ee3a4c7dddd0e25e059916cdc">I Heart Pumpkin: Comforting recipes for cooking with winter squash</a>.