Pour the fresh lemon juice into a large mixing bowl. Then prepare the apples by coring, peeling, and thinly slicing them. Drop each apple slice into the lemon juice as you go and stir them in.

Prepare the seasoning by combining the sugar, cinnamon, ginger and nutmeg in a small bowl. Sprinkle this seasoning over the apples and stir it all together until the apple slices are coated.

Rest the apple slices for at least 3 hours (and up to 6 hours) in the fridge.

Start making your pastry 1 hour before you wish to assemble and bake your pie.

In a large mixing bowl whisk together the cassava flour, oat flour, almond flour and flaxseeds.

Slice the butter very thinly directly from the fridge and add to the flour.

Rub the mixture between fingertips until roughly shorn. It’s okay that the butter is still in largish pieces.

Whisk in the caster sugar.

Make a well in the centre of the dry mixture and pour in the beaten eggs.

Bring the dough together using a wooden spoon at first, if you like, but switch to using your hands for the final gathering.

Turn the shaggy pastry out onto a clean work surface and knead for about two minutes until the dough comes together into a smooth ball which is no longer sticky. If the dough is still too dry and crumbly then add a little extra milk.

Split the dough into two even halves and roll into two balls. Flatten the balls slightly to make two thick round discs. Wrap each one in baking parchment and place in the fridge for 30 minutes - 1 hour to chill before rolling out.

Cut two large pieces of baking parchment, 2½ inches wider than the size you need to roll the pastry out to.

Place one of the chilled pastry discs between the parchment sheets.

Using a long rolling pin roll out the pastry into a round until it is about 5mm thick.

Peel away the baking parchment and use the rolling pin to lift the pastry and drape it over the pie dish.

Fit the pastry into the pie dish, patching up any cracking with excess pastry. Place the pie dish in the fridge whilst you roll out the second pastry disc in exactly the same way.

Bring your apple filling out of the fridge after you have rolled out the second disc. Toss the tapioca starch into the apple filling until totally absorbed.

Sprinkle the breadcrumbs on the pastry base into an even layer then spoon over the apple slices, layering them so that there are minimal gaps. Once the pie has been filled then pour all the apple filling juices over the top as well.

Drape the second disc of pastry carefully over the top of the pie. Press the edges of the pastry together then cut away the excess pastry to just beyond the pie dish. Roll the edges up together towards the pie to form a round ridge, make sure there are no gaps in the pastry. You can leave the edge of the pie like this or crimp it together using your fingers.

Make two 2-3cm slits in the centre of the pie lid using a sharp knife then place in the fridge for 30 minutes to chill.

Pre-heat the oven to 190°C / 170°C fan / gas mark 5.

Make the egg wash by whisking the egg with the milk.

Remove the pie from the fridge and brush the egg wash over lightly, making sure excess liquid does not gather in the creases of the pie which will make the crust unstable once cut. Sprinkle the Demerara sugar over the surface of the pie.

Place in the centre of the oven on the middle shelf and bake for 45 minutes when the pastry is golden.

Remove from the oven and allow the pie cool for at least 30 minutes on a wire rack before cutting to serve.