Prepare pie crust.
Melt butter in a pot.
Mix in flour and cook for 1 minute.
Add water and sugar, mix and cook for 3 minutes.
Leave to cool.
Peel and core apples and cut in fine pieces.
Mix with cinnamon and lemon juice.
Mix cold marinade with apples.
Roll out one part of pie crust and put in pie dish.
Spread in the apple filling.
Roll out the second part. Cut in 10 equal stripes.
Put 5 stripes on pie.
Lift every second stripe to weave the other 5 stripes through.
Fold in the ends of the stripes.
Flute the edges.
Mix egg yolk and milk and brush on pie lattice.
Bake in preheated oven at 200° C for about 1 hour. Place baking paper on oven bottom to avoid dripping apple sauce from burning.
Leave to cool.