Method

• 1.
  Place apple, sugars, lemon zest, flour and spices in a bowl and toss to combine. Cover with plastic wrap and set aside at room temperature overnight to extract liquid from the apples.

• 2.
  The next day, strain liquid into a pan and place over medium heat. Simmer, stirring, for 15 minutes, or until thickened and reduced (it should be the consistency of runny honey). Pour liquid back over the apples and set aside to cool completely.
• 3.
  Meanwhile, for the pastry, combine flours, sugar and seeds in a bowl with a pinch of fine salt. Using your fingers, rub in butter until it resembles coarse crumbs. Place vinegar in a jug with 1/2 cup (125ml) cold water and 4 ice cubes. Add to crumbs in 3 batches, combining with your hands until a dough forms. Divide into 2 balls, with 1 ball slightly larger. Enclose in plastic wrap and chill for 2 hours, or until cold.
• 4.
  Roll out larger pastry ball to 3mm thick on a lightly floured surface. Use to line base and sides of a 22cm springform pan.
• 5.
  Pour apple into pastry case, then roll out second pastry ball to 3mm thick and use to cover apple. Press edges together and trim to a 5cm border. Fold pastry edge over itself, then, using your thumb and forefinger, pinch the edges to form a fluted rim. Freeze for 10 minutes to firm up, then brush with beaten egg and scatter with demerara sugar.
• 6.
  Preheat the oven to 200°C/180°C fan-forced.
• 7.
  Place pie on a baking tray and bake for 45 minutes, then reduce temperature to 180°C/160°C fan-forced. Bake for a further 1 hour 10 minutes, or until pastry is golden.
• 8.
  Remove from oven and cool for 2-3 hours, then serve with thick custard.