Heat the oven to 170C (160C fan)/350F/ gas 4. Grease and line two 20cm round cake tins with baking paper.
Break the eggs into a large bowl, whisk, then add the vegetable oil and whisk again. Add the pumpkin puree and carrots and whisk again, until combined.
In a separate bowl, sift the flour, the spices and bicarb, add the sugar, then tip in the raisins and stir again. Combine the dry and the wet ingredients, add the vanilla and whisk until well incorporated.
Divide the mixture between two tins, and bake for about 25 minutes, or until a skewer inserted into the centre of the cake comes out clean. Set aside to cool.
Now make the carrot crisps. Using a peeler, shave the carrots into thin strips. Put in a bowl, drizzle with the oil and toss with the spices. Lay the carrot strips in two baking trays, making sure they do not overlap.
Bake for 10 minutes, rotating the tray halfway. Turn off the oven, open the door a crack and keep the trays in there for a further eight minutes. Remove from the oven and leave to cool completely, until crisp.
For the filling, combine the cream cheese and yoghurt, lightly whip with an electric mixer, sift in the icing sugar, and beat until smooth.
Add the double cream, beat again until it’s a spreadable and holdable consistency, then add the vanilla extract and maple syrup and beat again. Put a piece of clingfilm over the bowl and refrigerate until ready to use. This mixture is going to sandwich your cake together.
To assemble, put one layer of cooled sponge on to a plate, cover with half the Greek yoghurt filling, then sandwich with the second sponge. Swoosh the remaining filling on top of the cake. Finally, scatter with the carrot crisps.