Mix together the sugar, eggs, lemon zest and vanilla seeds. Stir in the butter, milk and salt. Mix the flour with the baking powder, stir into the mixture. Add the apples, mix. Transfer the mixture to the prepared tin.
Approx. 50 mins. in the lower half of an oven preheated to 180°C. Remove from the oven, allow to cool slightly, remove the tin frame. Slide the cake onto a cooling rack, leave to cool and dust with icing sugar.