Prepare the dough by mixing the dry ingredients.
Cut in the butter until crumbly.
Stir in the cold milk to form a dough.
Chill the dough for at least 30 minutes.
Prepare the apple filling while the dough chills.
Roll out the dough into a rectangle.
Spread the apple filling evenly over the dough.
Fold the dough over the filling to create a log.
Transfer to a baking sheet and brush with egg wash.
Bake in a preheated oven until golden brown.
Cool and dust with powdered sugar before serving.