Mix flour with baking powder in a large bowl. Stir in sugar and salt. Add the butter, vanilla essence and egg. Work everything into a smooth dough. Wrap and chill for 1 hour or overnight.
Peel apples, quarter, core and then finely dice either in the food processor or by hand.
In a cup mix 2 tablespoons sugar with cinnamon and toss with apples (use more or less of cinnamon-sugar depending on sweetness of apples).
Preheat oven to 190 degrees C. Grease a round springform cake tin with butter.
Line base and sides of tin with 2/3 of the chilled dough. Pour in apple mixture.
Roll out remaining dough into a circle. Place the circle of dough on top of the apples sealing the pastry together at the sides. If there is any leftover dough cut out pretty shapes and decorate the pie.
Bake in preheated oven for 40 minutes. Lower oven temperature to 180 degrees C and bake for an additional 30-40 minutes.