Start with the shortcrust pastry: combine the flour, salt, oil, and butter in a food processor.
Process (or pulse) until you start getting lumps.
Add the ice-cold water, then continue mixing until you get a sand-like texture.
Form the pastry dough into a disc and wrap it with a plastic --- chill in the refrigerator for at least thirty minutes.
Unwrap the dough and use it to line a 9-inch tart pan.
Preheat the oven to 200°C (375°F).
Peel, core, chop the apples, and arrange the slices on the pastry.
Combine the following in a bowl: flour, eggs, 1/3 cup of sugar, and crème fraiche.
If you have a hand mixer, use it to combine all the ingredients until you get a smooth texture.
Pour the custard mixture over the apple slices.
Mix the remaining sugar with the cinnamon powder and sprinkle on top.
Place your Alsatian apple tart in the middle of the oven for forty to forty-five minutes or until it turns golden.
Remove from the oven and set aside for at least fifteen minutes to cool.
Transfer to a serving plate, and sprinkle with more sugared cinnamon, if preferred --- then serve!