1. Preheat the oven to 200C/gas 6. Roll out the pastry thinly and use it to line a 23cm tart tin.
2. Beat the eggs together with the sugar, salt and spices. Add the pumpkin purée, coffee liqueur, double cream and soured cream and stir well until combined.
3. Pour the mixture into the pastry case and bake for 15 minutes. Lower the heat to 190C/gas 5 and continue cooking for another 45 minutes.
4. Remove the tart from oven and leave to cool to room temperature.
5. For the whisky cream: whisk all the ingredients together until thick.
6. Dust the pie with icing sugar and serve with the whisky cream.