In the bowl of a food processor, place the flours, Xanthan, salt and spices. Blitz for a few seconds to incorporate.
Add cold, cubed butter to the food processor and blitz until it resembles fine breadcrumbs.
Remove the blade from the processor bowl and add the eggs and ice cold water and fork together until a sticky dough forms.
Turn out onto a lightly floured piece of baking paper and work together until you have a flat disc type shape. Wrap tightly in glad wrap and place into the fridge for 15 minutes.
While that's chilling you can prepare your filling: -
Preheat your oven to 190 Degrees Celsius.
Core and slice your apples into thin crescents and place into a bowl. Add melted butter and additional spices. Toss to combine and set aside.
Once pastry has chilled, take a large clean sheet of baking paper (as large as your baking tray) and very lightly flour it. Turn your cold pastry disc out onto it and start rolling it out into a large flat disc.
You want to a roughly round shape here, but overall it doesn't matter as we're going for a rustic look! Keep evenly rolling out until it's at least 1/2cm thick, though the thinner the better.
Brush the top of the pastry with beaten egg and sprinkle the tablespoon of almond meal over top. Finish by tumbling the apple slices into the middle and roughly arranging. Be sure to leave a few cm's of pastry bare around the entire edge.
Now take the edges of the pastry and pinch and pull it roughly over the edge of the apples. You can be as delicate and decorative as you like here. Once happy, slide the baking paper and tart onto your tray and straight into a moderate oven for 25 minutes.
Simply cut rough pieces and serve with vanilla ice cream or a dollop of thick cream. Enjoy warm or cold over the next few days. Keep in an air tight container for 4-5 days.