Preheat the oven to 180°C. Grease and line a 20cm cake tin with a removable base
Place the butter in the bowl of an electric mixer and beat until pale and fluffy. Add 4 tbsp of the flour, and then beat in the eggs one at a time. Fold in the remaining flour, baking powder and cinnamon. Add the maple syrup, vanilla and apple, and gently fold until just combined
Pour the batter into the prepared tin. Transfer into the oven and bake for 40-50 minutes or until a skewer inserted comes out clean. Remove from the oven and cool for 15 minutes, before turning the cake out of the tin
Serve the cake warm or at room temperature, and with a spoonful of vanilla yoghurt and a dusting of icing sugar (optional)