Sift the cake flour and baking powder twice into a bowl.

Add brown sugar and salt, then mix lightly.

Cut the cold butter into cubes and use a scraper to mix until it resembles coarse crumbs.

Beat the egg and add it to the mixture, stirring to combine.

Add coffee extract and chocolate chunks, then mix lightly.

Form the dough into a ball, wrap it, and refrigerate for 1 hour.

Roll out the dough, shape it, and brush the top with egg wash.