Preheat oven to 190C. Line a 23cm spring form baking tin with greaseproof paper.
Core the apple and cut it into moon-shaped slices, about 1 cm thick and keep aside.
Mix the eggs together with the sugar with an electric mixer for a couple of minutes, until pale.
Add the oil, cinnamon and a pinch of salt and mix again for another couple of minutes. Finally add the flour and the baking powder and whisk again for another minute or two. Keep on whisking even after you think it’s enough!
Pour a bit more than half of the apple slices into the cake mixture, stir and pour everything into the baking tin.
Arrange the remaining apples on top, pushing them very slightly into the mixture but still visible on the surface. You may like to create a pattern as they will be visible once the cake is baked.
Bake for 50-60 minutes. To check if the cake is cooked insert a skewer or toothpick; if the cake is cooked it will come out dry and clean. If still wet bake for another 5 minutes and check again.
Leave to cool for at least 20 minutes before removing it from the tray. l Slice with a sharp knife to serve or the large chunks of apples inside may cause it to crumble.
