For the filo pastry, sift the flour and salt together. Add the water and oil and mix until a sticky dough forms. Knead for approximately 10 minutes, or until smooth and less sticky.
Place in bowl, cover with cling film and set aside to rest for an hour.
When the pastry is rested, cut it into 10 equal portions.
Generously flour a large work surface, start to roll out one portion of pastry using a rolling pin. Once you’ve got it relatively thin, you can use a 2cm/1in diameter dowel or rod instead (this will make it easier to achieve the thinnest pastry). Roll the pastry out as thinly as possible then stretch it even thinner by running your hands under it and very gently tugging on the dough. Repeat for all the remaining pieces, keeping the filo covered with damp cloth while you work.
For the filling, cream the butter and icing sugar together. Mix in the eggs in one at a time, making sure they are combined before adding the next. Add the ground almonds and mix well.
In a small pan, heat the cardamom pods and orange juice to infuse. Simmer for a few minutes, then allow to cool.
When cool, remove the cardamom pods and add the juice to the butter and egg mixture along with the three-quarters of the orange zest, the dates and flaked almonds. Mix well.
Preheat the oven to 180C/350F/Gas 4.
Put the filo sheets on a long table (about 2m/6ft long) side by side with the edges slightly overlapping each other to form a very long rectangle approximately 2m/6ft long.
Spoon the filling in a straight line near the edge of a long side of the pastry. Then, just like a Swiss roll, begin to roll up the pastry until you have a very long, thin roll of pastry. Wrap up into a swirl, to resemble a coiled snake.
Place on the baking tray and bake in the oven for 40-45 minutes, or until the pastry is golden-brown and crisp.
To serve, dust with icing sugar and scatter with flaked almonds. Finish with the reserved orange zest and some crushed pistachios.