Mix flour, butter, cinnamon, vanilla sugar, sugar, and salt together until sandy.
Add eggs and mix briefly. Form a flat ball and wrap in plastic wrap.
Let it firm up in the refrigerator for 1 hour.
Peel all apples and remove the core with an apple corer.
Cut in half and slice into thin slices, keeping them stuck together.
1 apple is cut into small cubes and the less pretty slices are also cut finely.
Combine them in a bowl, mix in sugar and cornstarch, and stir well together.
Roll the dough evenly with some flour. It can also be done between 2 sheets of baking paper if you're not confident, it will definitely work too.
Line your pie pan with it. Press well into the sides, roll with your rolling pin over your baking pan with dough. This way you cut the dough to fit. With the rest of the dough, cut strips to decorate the sides; if it is too sticky or soft, put it back in the fridge to firm up.
Evenly distribute the finely chopped apple mixture over the bottom.
Take the sliced apples, press them a bit apart, and lay them overlapping on top.
Brush some melted butter over the apples and decorate the sides with crisscross strips of dough.
Beat the yolk with some water and brush it over the edges of the dough.
Bake for 1 hour at 165-170°C until the apples are nicely colored.
Let the pie cool. By the way, it also goes well with a scoop of vanilla ice cream, haha.