Mix flour, cold butter, salt, and sugar together.

Cut the butter into small pieces within the flour mixture.

Add 30g of cold water and quickly knead into a dough.

Wrap the dough in plastic wrap and refrigerate for 1 hour.

Chop the apple into small pieces and melt butter in a pan.

Add chopped apple, cinnamon, sugar, and a pinch of salt to the pan. Cook for 10 minutes on medium heat.

Roll out the chilled dough to a thickness of 0.3cm.

Place the rolled dough into a pie tin and trim the edges.

Poke holes in the dough with a fork to prevent bubbling.

Add the apple filling into the pie crust.

Cut remaining dough into strips and arrange in a lattice pattern on top.

Brush the top with egg yolk for a golden finish.