Pulse flour, butter, orange zest, sugar, and salt in a food processor until breadcrumb texture forms.
Add egg yolks and pulse until a rough dough forms.
Knead dough until smooth, shape into a disc, wrap in film, and refrigerate.
Heat apples and sugar in a saucepan for five minutes until slightly broken down.
Stir in cornflour, vanilla, and cinnamon, then cook for two minutes and cool.
Preheat the oven to 200°C.
Roll out two-thirds of the pastry to line a 23cm pie tin.
Blind bake with greaseproof paper and baking beans for 15 minutes.
Remove beans and paper and bake for 10 minutes until crisp.
Fill the pastry base with apple mixture and cover with the remaining rolled pastry.
Bake for 20-25 minutes until golden-brown.
Simmer milk, cream, vanilla pod, and seeds in a pan, then remove from heat.
Whisk egg yolks and sugar, then slowly whisk in the strained hot milk mixture.
Cook mixture in a clean pan for five minutes until thickened.