Unless you are using apple sauce from a jar, peel and core the apples and chop into small chunks, then put them in a pan with about 30 ml apple juice or water, put the lid on and cook over a low to medium heat for about 20-30 minutes, stirring now and then, until mushy (a thick apple sauce). Add more liquid if it gets too dry. Spoon into a bowl and leave to cool.
Preheat the oven to 180 degrees C. Lightly brush the base and sides of a deep 23cm round / 20 cm square loose bottomed cake tin with a little vegetable or sunflower oil, then line the base with baking paper.
Grate the carrots by hand or in a food processor, then put them in a mixing bowl and add the apple sauce, Sweet Freedom*, two whole eggs and orange zest. Sift in the flour, cocoa powder, baking powder, bicarbonate of soda and cinnamon, if using, and beat until well mixed.
Whisk the egg whites to stiff peaks, carefully fold into the cake mixture, then fold in the chocolate.
Pour or spoon into the tin and bake for 30-40 minutes until a skewer comes out clean when inserted in the centre. Leave to cool in the tin for an hour before turning out onto a wire rack to cool completely (because it is so moist, it may break up if you try to turn it out while too hot).**
Dust with icing sugar before serving.