Preheat the oven to 180C (160C Fan). Line an 8” cake tin with greaseproof paper and leave to one side.
Peel and core 3 of the large apples. Cut into 1cm chunks and place into a large bowl.
Add 2tbsp of light brown sugar and cinnamon to the bowl and mix until the apples are coated. Leave to one side.
In a large bowl, cream together the butter and sugar until light, pale and fluffy.
Add in the flour, eggs, cinnamon, mixed spice and baking powder and mix until all the ingredients are completely combined.
Fold through the apples until they are evenly distributed.
Pour the mixture into your cake tin.
Peel and core your fourth apple. Cut into slices and place onto the top of your cake mixture. Sprinkle over the final 2 tbsp of light brown sugar and bake in the oven for 45-50 minutes.
The cake is baked when it is golden brown on top. Leave the cake to cool in the cake tin for 15-20 minutes before removing and leaving to cool fully on a wire rack.