Line, grease and flour a 20cm round cake tin. Preheat oven to 190 °c.
Put egg yolks and sugar in a heat-proof bowl. Place bowl over a deep pan of steaming hot water. (do make sure that the bowl does not touch the hot water.) whisk the eggs until the mixture is thick and pale.
Bring the bowl away from the pan and add the grated carrots and chopped apple.
Combine sifted ingredients with the ground almonds, hazelnuts, chopped ginger and lemon rind.
Whisk egg whites until soft peaks form then add the sugar gradually and continue to whisk until stiff.
Fold one-third of the meringue into the carrot mixture with a large metal spoon. Alternate with one-third of the combined sifted ingredients. Gently fold in the next one-third of meringue, followed by another one-third of the sifted ingredients.
Repeat with the last one-third portion of meringue and sifted ingredients to combine. All this should be done in a gentle manner so as to retain the air in the mixture. Do not overbeat or overfold, or you will lose the air in the mixture.
Pour batter into prepared tin. Bake in preheated oven for 60 minutes or until a skewer comes out clean when inserted into the centre.
Cool cake in baking tin for 10 to 15 minutes, then transfer onto wire rack to cool.