Preheat oven to 200°C. Grease a shallow ceramic 20cm pie dish and line a baking tray with baking paper.
Place flour and salt onto a clean work bench and toss butter through. Lightly rub to partially combine. Make a well in the centre and pour in water. Work into a rough heap of buttery lumps of dough
Knead lightly, press into a flat round ball and dust with a little flour. Wrap in cling wrap and chill in refrigerator for 15 minutes.
Place a sheet of baking paper onto a work bench and dust with flour. Roll out pastry to about 26cm, dusting generously with flour as necessary. Use baking paper to flip pastry into dish and peel away paper. Press down firmly around the edges and trim excess. Use a fork to prick bottom of pie.
Line pastry with a sheet of baking paper and fill with pastry weights. Bake for 15 minutes and remove weights and baking paper. Bake for a further 5-10 minutes, or until a golden crust has formed and the pastry is cooked through. Remove from oven and cool.
For apple halva, mix lemon juice and sugar in a small bowl and sprinkle over apples to prevent them from browning.
Melt butter in a large heavy based saucepan. Fry off cinnamon sticks and cloves and add the apple mixture when fragrant. Lower heat to medium and cook for ten minutes, stirring occasionally.
Add condensed milk, raisins, almonds and rosewater. Cook for ten minutes, stirring continuously until it resembles porridge. Stir in ground cardamom, remove from heat and cool.
Reduce oven to 180°C and roll out readymade short crust onto a flour-dusted work bench. Cut out ten diamond shapes half the width of the pie dish.
Place diamonds onto prepared baking tray and brush with beaten egg. Sprinkle with pistachios and caster sugar. Bake for 7-10 minutes until golden.
Place apple halva mix into pastry base and arrange cooked pastry diamonds on top. Add pistachios to centre and sprinkle a few around. Very lightly sprinkle caster sugar onto pastry only.
To serve, place pie on a serving board with a jug of double cream with a few drops of rosewater stirred in. Scatter rose petals around board to decorate.