Apfelkuchen are revered in Germany, and this moist cake with a crunchy cinnamon topping will show you why.
Preheat the oven to 170C/150C Fan/Gas 3. Butter and line a 23cm/9in round cake tin.
Coat the apple wedges in the lemon juice and set aside.
In a large bowl, beat together the butter and sugar, using an electric hand mixer, until pale and fluffy. Add the eggs and beat until smooth. Sift in the flour, baking powder and salt and mix well. Slowly add the milk, mixing well after each addition, until you have a smooth batter.
Transfer the batter to the cake tin. Arrange the apple slices, flat-side down, on the batter in a spiral pattern.
For the topping, mix together the demerara sugar and cinnamon. Sprinkle over the batter.
Bake in the middle of the oven for 40–45 minutes, or until a skewer inserted in the centre of the cake comes out clean and the top is golden-brown. Leave to cool for 15 minutes in the tin. Run a knife around the edges of the cake and turn it out of the tin onto a wire rack.
Serve warm or at room temperature with whipped cream.
