My mum's apple pie

I think this apple pie tradition was started by my grand-grandmother. Then she taught my grandmother and then, again, the tradition passed onto my mum and her sister. Yes, they all bake apple pie from this one and unique recipe. Maybe it is not very sophisticated or complicated but this cake always reminds me of home, childhood and all good memories.
As I am a bit home-sick recently, here it is...

Ingredients:

150g unsalted butter, soften
2 cups normal flour
4 egg yolks
4 tsp sour cream
4 tsp sugar
2 tsp baking powder
apple sauce, I usually use quite a lot...
cinnamon

Mix butter, flour, sugar, baking powder and egg yolks to make nice and hard dough. It needs to stay in a fridge for at least 20 minutes to cool down. In the meantime preheat oven to 180C and mix apple sauce with cinnamon.
When dough is cold, divide into two and set one half aside. Use shallow pie tin, slightly greased with butter and arrange dough to make pie's bottom. Put apple and cinnamon mix on top then use other half of dough to make upper part. Arrange as you like it- stripes, stars, circles, anything you can imagine!
Bake until golden.
Delicious served warm with custard or ice-cream or cold with cup of tea.