Preheat the oven to 180 C / Gas 4. Grease and line a 25cm loose bottomed cake tin.
In a large mixing bowl beat together the butter and sugar until light and fluffy. Add the eggs, one at a time then fold in the flour, baking powder, spices and orange zest. Spoon into the prepared cake tin then layer the thinly sliced apple on top.
Bake in the preheated oven for 90 minutes or until a skewer inserted into the centre comes out clean. Remove from the oven and allow to cool in the tin. Dust with icing sugar to serve.