Preheat the oven to 230 C / Gas 8. Grease a pie dish and flour lightly.
For the pastry:
Combine the flour, salt and sugar in a large bowl. Mix with fork.
Mix the Stork® into the flour with fork or using a food processor.
As soon as the mixture becomes really lumpy, begin adding 1 tablespoon of water at a time. Lift and toss the mixture until it forms a dough. Add more water or flour if necessary; it is better the pastry be too wet than too dry.
Gather the dough and separate into two balls (if the dough crumbles easily, add a little more water).
Dust the counter top with flour and roll each ball into the size of your pie dish, adding an extra 5cm all the way around.
Place the bottom layer into the prepared pie dish and place in the fridge, while making the filling.
For the filling:
In a large bowl, mix the diced rhubarb, flour, sugar and cinnamon. Remove the pastry dish from the fridge and spoon in the filling. Cover with a second layer of pastry and press the edges of both upper and lower pastry layers together to seal. Create a hole for ventilation at the top.
Bake for 15 minutes in the preheated oven then reduce the heat to 180 C / Gas 4 and bake for a further 35 minutes or until juice comes out of the ventilation holes.