Low-fat chocolate sponge cake recipe
 This chocolate cake contains no butter or oil so is naturally lower in fat than a classic chocolate sponge. The addition of grated apple makes the sponge moist and its natural sweetness means you can afford to use less caster sugar. olive oil cooking spray, for greasing4 large free-range egg whitespinch salt2 large free-range eggs1 tsp vanilla extract75g/2½oz golden caster sugar2 Braeburn apples, peeled, cored and grated100g/3½oz self-raising flour, sifted40g/1½oz cocoa powder, sifted olive oil cooking spray, for greasing 4 large free-range egg whites pinch salt 2 large free-range eggs 1 tsp vanilla extract 75g/2½oz golden caster sugar 2 Braeburn apples, peeled, cored and grated 100g/3½oz self-raising flour, sifted 40g/1½oz cocoa powder, sifted 150g/5½oz raspberries75g/2½oz icing sugar, sifted, plus extra for dusting 150g/5½oz raspberries 75g/2½oz icing sugar, sifted, plus extra for dusting Method Preheat the oven to 170C/330F/Gas 3.Grease a 20cm/8in non-stick cake tin with a little olive oil cooking spray. Using an electric hand whisk, beat the egg whites with a pinch of salt until stiff peaks form when the whisk is removed from the bowl, then set aside. In a separate bowl, whisk together the whole eggs, vanilla extract and caster sugar until pale, doubled in volume and the sugar has dissolved.Fold in the apple, flour and cocoa powder with a metal spoon and then fold a third of the egg white mixture into the cocoa mixture. Once combined, fold this into the remaining egg white mixture.Spoon the mixture gently into the cake tin and bake for 30 minutes, or until risen (when cooked the sponge should bounce back when pressed lightly). Transfer to a wire rack and leave to cool. Once cooled, slice the cake in half horizontally to create two layers. Mash two-thirds of the raspberries and one tablespoon of icing sugar together roughly in a bowl and spread this mixture over the top of one of the pieces of cake. Top with the other piece.Mix together the remaining icing sugar and enough water to bring it together to form a thin icing of drizzling consistency. Drizzle the icing over the cake, leave for 2-3 minutes to harden slightly and then decorate with the remaining raspberries. Preheat the oven to 170C/330F/Gas 3. Preheat the oven to 170C/330F/Gas 3. Grease a 20cm/8in non-stick cake tin with a little olive oil cooking spray. Using an electric hand whisk, beat the egg whites with a pinch of salt until stiff peaks form when the whisk is removed from the bowl, then set aside. Grease a 20cm/8in non-stick cake tin with a little olive oil cooking spray. Using an electric hand whisk, beat the egg whites with a pinch of salt until stiff peaks form when the whisk is removed from the bowl, then set aside. In a separate bowl, whisk together the whole eggs, vanilla extract and caster sugar until pale, doubled in volume and the sugar has dissolved. In a separate bowl, whisk together the whole eggs, vanilla extract and caster sugar until pale, doubled in volume and the sugar has dissolved. Fold in the apple, flour and cocoa powder with a metal spoon and then fold a third of the egg white mixture into the cocoa mixture. Once combined, fold this into the remaining egg white mixture. Fold in the apple, flour and cocoa powder with a metal spoon and then fold a third of the egg white mixture into the cocoa mixture. Once combined, fold this into the remaining egg white mixture. Spoon the mixture gently into the cake tin and bake for 30 minutes, or until risen (when cooked the sponge should bounce back when pressed lightly). Transfer to a wire rack and leave to cool. Spoon the mixture gently into the cake tin and bake for 30 minutes, or until risen (when cooked the sponge should bounce back when pressed lightly). Transfer to a wire rack and leave to cool. Once cooled, slice the cake in half horizontally to create two layers. Mash two-thirds of the raspberries and one tablespoon of icing sugar together roughly in a bowl and spread this mixture over the top of one of the pieces of cake. Top with the other piece. Once cooled, slice the cake in half horizontally to create two layers. Mash two-thirds of the raspberries and one tablespoon of icing sugar together roughly in a bowl and spread this mixture over the top of one of the pieces of cake. Top with the other piece. Mix together the remaining icing sugar and enough water to bring it together to form a thin icing of drizzling consistency. Drizzle the icing over the cake, leave for 2-3 minutes to harden slightly and then decorate with the remaining raspberries. Mix together the remaining icing sugar and enough water to bring it together to form a thin icing of drizzling consistency. Drizzle the icing over the cake, leave for 2-3 minutes to harden slightly and then decorate with the remaining raspberries.