Place the flour, butter and salt into a food processor and blend for 10 seconds, then add the water and blend until a ball of pastry is formed. This should only take a matter of seconds. Cover with cling film and place into the fridge to chill for at least an hour.
Preheat the oven to 180°C / fan 160°C / gas 4.
Roll out the pastry and line a greased deep pie dish. Reserve some pastry for the lid.
Combine all of the filling ingredients in a large bowl then spoon into the pie dish.
Roll out the remaining pastry place it loosely over the top of the pie. Use the back of a fork crimp down the edges.
Brush the pastry with the soya milk and dust with sugar then bake for 1 hour 15 minutes or until golden brown.
