Preheat oven to 190°C/fan 170°C/gas mark 5.
Rub the Fate Low Protein all-purpose mix, margarine and caster sugar together in a mixing bowl, until it resembles coarse breadcrumbs.
Add the water to the Fate mixture and mix to form the pastry dough.
Leave to rest for 10 minutes.
Dust a clean work surface with Fate Low Protein All-Purpose Mix and knead the pastry for 1 minute, until smooth.
Divide the pastry into 2 balls and using a rolling pin, roll the pastry out between two pieces of grease proof paper to 258cm diameter circles.
Lift one pastry circle into the pastry case dish and press the pastry around the edge of the dish using your thumb.
Cut the excess pastry off the sides of the tin dish and using a fork, prick the pastry base and set aside.
Heat the apples, muscovado sugar and butter and stir in a pan over a medium heat.
Cook until the apples are soft and pour into the pastry case.
Top with the second pastry circle and crimp around the edges.
Brush with the ProZero and make two small slashes in the lid to allow the steam to escape.
Bake in the oven for 25 minutes or until golden brown.
Serve with low protein cream or ice cream.
For a touch of spice, add 1 tbsp cinnamon into the apples when they are cooking.
Fate Low Protein All-Purpose Mix and ProZero are foods for special medical purposes and should be used under medical supervision.