To make the pastry, rub the Fate low protein all-purpose mix, margarine and sugar together in a mixing bowl until it resembles coarse breadcrumbs.
Add the water and combine until a pastry dough ball is formed.
Leave to rest for 10 minutes.
Dust a clean work surface with Fate low protein all-purpose mix and knead the pastry for a minute on the work surface until smooth.
Roll the pastry out with a rolling pin and place in the lined pie dish.
Preheat the oven to 200°C/180°C fan/gas mark 6.
To make the filling, place the pumpkin, brown sugar, mixed spice, golden syrup and butter in a saucepan and cook over a medium heat for 15 mins or until tender.
Blend the mixture until smooth.
In a separate bowl, cream together the sugar and margarine.
Add the Fate Low Protein All-Purpose Mix and the baking powder and rub together with your fingertips until it resembles breadcrumbs.
In another bowl, mix the ProZero, egg replacer and vanilla essence.
Add the ProZero mixture to the dry mixture and stir until well combined.
Finally, add the pumpkin mixture and stir until well combined.
Arrange the marshmallows evenly over the pastry base.
Pour the pumpkin mixture on top and bake in the oven for 30 minutes.
Remove from the oven and leave to cool.
Before serving dust with icing sugar and cinnamon.
Fate Low Protein All-Purpose Mix and ProZero are foods for special medical purposes and must be used under medical supervision.