To make the pastry, place the flour, sugar and butter into the Thremomix bowl and mix on Speed 6 for 10 seconds (or until it resembles fine breadcrumbs). Add the iced water and knead for 2 minutes on interval speed. Knead the dough into a ball on a lightly floured surface, wrap in plastic wrap and place into the fridge for at least 30 minutes. When you're ready to use your dough, divide it into 2 portions (one ⅔ for the base and one ⅓ for the top) and then roll out each portion until 3-5mm thick. If using store-bought pastry sheets, place them onto the bench to defrost.
Preheat oven to 190 degrees celsius (180 if using fan forced). Grease a 24cm pie dish and set aside.
Place the apple slices into the Varoma dish. Fill the Thermomix bowl with 500g water and cook for 15 minutes, Speed 2, Varoma temperature.
Sprinkle over the sugar, lemon juice and cinnamon and mix to combine.
Place the larger piece of pastry over the pie dish and press down so that it covers the base and sides. Trim any excess.
Drain any excess liquid from the apple mixture. Add the apple mixture to the pie dish and spread out evenly.
Place the smaller piece of pastry over the apples, and crimp the edges lightly with your fingertips to seal around the rim of the dish.
Brush the lightly beaten egg over the top of the pie. Sprinkle over the remaining raw sugar (optional).
Cut 3-4 slits into the top of the pastry.
Bake in the oven for 30-40 minutes or until the pie pastry is lightly golden and crispy.