Preheat oven to 190°C/fan 170°C/gas mark 5.
Rub the Fate low protein all-purpose mix and the margarine together in a mixing bowl until it resembles coarse breadcrumbs.
Mix the sugar into the water until dissolved and combine with the Fate mixture.
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 between two pieces of grease proof paper, with a rolling pin to a 28cm circle and using the rolling pin lift into the 24cm baking tin making sure that you press the edges.
Leave to stand for 5 minutes.
Cut the excess pastry off the sides.
Add the jam to the pastry base and spread evenly using the back of a spoon.
To make the sponge filling, cream together the sugar and margarine in a bowl.
Add the Fate Low Protein All-Purpose Mix and the baking powder and rub together with your fingertips until it resembles breadcrumbs.
In a separate bowl, mix together the ProZero, egg replacer and almond extract.
Add the ProZero mixture to the dry mixture and mix until well combined.
Layer evenly over the pastry and jam base.
Bake in the oven on the middle shelf for 25 minutes.
Once baked, remove from the oven and allow to cool on a wire rack.
For the icing, in a bowl, combine the water and icing sugar and mix into a paste.
Once the tart is fully cooled, cover with the icing.
Decorate with glacier cherries to taste.
Fate Low Protein All-Purpose Mix and ProZero are foods for special medical purposes and must be used under medical supervision.