Preheat the oven to 180oC, gas mark 4.
Grease and line the base of a 21 cm round cake tin with baking parchment.
Mix together the flours, baking powder and sugar.
In a separate bowl, whisk the eggs and rapeseed oil until creamy.
Fold the egg mixture into the flour mixture, along with the carrots.
Spoon into the tin and bake for 45 minutes until cooked throughout.
Cool slightly before removing from the tin.
Allow to cool completely.
Whisk together the soft cheese, icing sugar and lemon juice.
Spread the icing on the cooled cake.
Decorate with the lemon zest.
Ideal for freezing.