Preheat your oven to 140⁰C / Fan 120⁰C / Gas Mark 2 then line a large rectangular tin (approx 21x29cm).
Mix the flour, caster sugar, brown sugar, bicarbonate of soda, cinnamon, nutmeg and ginger in a large bowl, mixing thoroughly to ensure all lumps have dispersed.
In a separate bowl whisk the eggs, milk and sunflower oil together, until a little frothy then add to the flour mix.
Add the pumpkin and sultanas then stir well.
Pour into your prepared tin then bake in the centre of your oven for 50-55 minutes until golden brown. To check the cake is cooked simply insert a skewer into the centre - if it comes out clean then it’s cooked.
Leave to cool for 10 minutes then turn out onto a cooling rack - have the base of the cake to the top to give you a flatter surface to decorate - then leave to cool completely.
Meanwhile make your spiders... set aside 8 of the chocolate buttons to finish the top with then melt two thirds in a microwave or over a pan of boiling water until smooth and runny. Remove from the heat then stir in the remaining third.
One at a time dip each date into the chocolate with a fork until fully coated. Shake off any excess chocolate then place onto a sheet of greaseproof paper, before the chocolate has fully set add on marshmallow eyes and pretzel legs. Repeat for the other 3 dates.
When your cake has cooled completely, roll out the icing to the same size as your tin (use your tin as a template).
Spread the jam over the top of the cake then lay over the rolled out icing.
Using a fine nozzle draw a spider web design with the black piping icing, arrange the set aside chocolate buttons on the edges then carefully place the spiders in the web.