For the spelt and apple cake, first knead all the ingredients for the dough, form into a ball and wrap in plastic wrap. Refrigerate for about 30 minutes.
For the filling, wash, core (peel if necessary) and grate the apples. Mix with the remaining ingredients.
Grease a tart pan. Preheat the oven to 200 °C.
Divide the dough in half and roll out each half thinly, round. Line the tart pan with one half of the dough. Spread apple mixture on top and cover with remaining dough. Prick a few times with a fork.
Whisk the yolk and spread it on the dough cover. Bake the spelt-curd apple pie for about 30 minutes.