Roll out the pastry and line your pie dish. We used a deep-sided pie dish, approximately 22 centimetres diameter. Trim the edges and flute them—so they look good on Instagram!
Mix together the castor sugar, flour and ground cinnamon.
Toss the apple slices in the mixture until they are well coated and arrange them in the pastry shell. Dot the apples with cubes of butter.
Refrigerate while you make the crumble.
Preheat the oven to 170°C.
To make the crumble, place the butter, sugar, vanilla paste and salt into the Thermomix bowl and cream 30 seconds/speed 5.
Add remaining ingredients except almonds and combine 10 seconds/Reverse/speed 5.
Scrape down the sides of the bowl, add the almonds and mix 5 seconds/Reverse/speed 3.
Place crumble on top of the apples making sure you seal the edges as well as you can. Rustic is good, but you want closure. Add a few more whole almonds on top and cover the entire pie with foil.
Bake for 45 minutes with the foil covering. Remove foil and bake a further 15 minutes until golden, fragrant and the apples are cooked. (Test with a skewer.)
Serve warm or cold, with ice cream or whipped cream, though ice cream is pretty well a rule if you are sticking with the American theme.