Preheat oven to 180 degrees C. Lightly grease and flour two 23cm round cake tins.
Separate eggs and beat egg whites until frothy, then continue whisking and gradually add 1/2 cup of the white sugar. Beat until stiff.
In a large bowl combine the cake flour, wheat flour, brown sugar, baking powder, bicarb soda and cinnamon then mix until blended. Add the oil and the buttermilk and mix well. Add the egg yolks and mix well. Fold in the egg whites and then the carrots. Pour batter into prepared pan.