Cream the softened butter together with the sugar and salt. Fold in one egg at a time and add the lemon zest and vanilla flavoring. Fold in the milk by the spoonful. Finally, fold in the sifted flour mixed with baking powder. Rest the dough briefly in the baking bowl with the lid closed.
Butter the cake springform pan and dust with flour. Fill half of the dough into the pan and top with apple slices. Pour the remaining batter on top and top with the remaining apple slices.
Bake the apple pie over medium heat for about 30 to 40 min until golden. Remove from the pan and cool on a cooling rack. The cake is served cooled.