PASTRY STEPS: 1-4, and 10
Grease a 10 inch cake tin (ideally a spring-form or one with a lifting bottom) with butter or cooking oil and set aside.
Cut the vanilla bean in half the long way and scrape the seeds out from the inside. (Note that you can do the whole bean at once and save half of the paste for the filling and half for the crust, or you can keep half a bean set aside for when you do the filling steps).
To make the crust, combine the dry ingredients and paste from half of a vanilla bean in a food processor and mix thoroughly. Add the cold butter and combine until the mixture forms small crumbs. Add one egg and pulse together again, stopping when the dough is evenly mixed.
Press about 3/4 of the dough into the bottom of the cake tin in order to make an even crust. Roll the remaining dough into a ball and wrap in plastic wrap. Set everything aside to chill in the refrigerator.
Preheat oven to 350° F (175° C).
FILLING STEPS: 6-9
If you're using whole blanched almonds (see note below), pulverize them with a food processor or nut/spice grinder. Set aside.
Peel and slice the apples. You can be relatively flexible on the size of the apple pieces, but I like large 'chips' of apple, about 2-3 cm (1 inch) long and 1/2 cm (less than 1/4 inch) thick. If you have a hand-cranked apple peeler, it makes quick work of this and cuts your apples into an ideal thickness.
Combine the almond flour, flour, sugar, and spices in a large bowl. Scrape the seeds out of the 1/2 vanilla pod and add them to the mixture. Add the butter and eggs and combine with a hand mixer. Once the filling is well combined, fold in the sliced apples.
Pour the filling evenly into the cake tin.
Roll out the remaining chilled pastry. It should be about 1/4 cm (1/8 inch) thick. Cut the pastry into shapes of your choosing and layer them on top of the cake. They do not need to cover the entire surface of the cake.
Bake for about 1 hour, or until the center is set and the top is golden. Serve warm or chilled, topped with vanilla sauce.