To make the pastry, briefly blend the flour, nuts, sugar, cinnamon, sea salt and vanilla paste in a food processor. Add the chilled butter and vegetable shortening and pulse until the mixture looks like coarse breadcrumbs. Add the orange zest and the beaten egg and pulse again. Remove the lid and press some of the mixture together, if it looks a little dry or cracks when pressed together add a tablespoon of chilled water. You may need more or none at all depending on the moisture in the ingredients.
Tip the dough onto your work surface and form it into a ball, flatten and wrap in clingfilm. Refrigerate until just firm enough to roll out – about 30 minutes.
Make the filling by peeling, coring and slicing the apples thinly. Place in a bowl, squeeze in the orange juice and then add all the other ingredients.
Butter and lightly flour a 30cm pizza or baking dish. Roll out 1/3 of the dough on floured work surface to approximately 34cm round and line the base, pressing it gently into place. The pastry will be larger than the base, but you will use this to form and edge for the lid.
Fold the edges of the pastry in so it forms a boarder all the way round. Brush with beaten egg, then sprinkle the ground rice over the pastry base. Pile in the filling, roll out the rest of the pastry to cover the top. Press the edges together and pinch using your index finger and thumb creating a decorative finish. Cover and chill until cold – about 30 minutes.
Glaze the top with egg wash and sprinkle with demerara sugar.
Bake in a preheated oven 180°C/ Fan 160°C/Gas 4 and cook for 25 minutes, then turn down the oven to 150°C/Fan 130°C/Gas 3 and cook for a further 20 minutes. The finished pie should be beautifully golden. Serve warm with whipped double cream, Greek yoghurt or crème fraîche