- 225g/8oz caster sugar
- 165g/5½oz plain flour, plus extra for dusting
- 3 free-range eggs
- 1 tbsp butter, for greasing
- 2-3 Granny Smith apples, peeled, cored and sliced
- Preheat the oven to 180C/355F/Gas 4.
- Place the caster sugar, flour and eggs into a bowl and whisk together to make a thick smooth batter.
- Grease and flour a deep baking dish and arrange all the apple slices to cover the bottom of the dish.
- Spoon the batter mixture over the top and transfer to the oven to bake for 30-40 minutes. (To check if the sponge is ready, insert a skewer into the top of the sponge, if it comes out sticky, return to the oven to cook for another 5 minutes.)