Preheat oven at 180C fan
Line a loaf tin with greaseproof paper
Sift flour and set aside
In a separate bowl lightly beat the eggs
In your mixing bowl add softened butter, sugar and lemon zest and mix until pale and fluffy
Turn down the speed and add about a fifth of the beaten eggs, combine well, then follow with 2 tablespoon full of flour and repeat until until all the egg is used. That should leave some flour left which you'l gently fold into the batter.
Transfer the batter into your lined loaf tin
Bake for 10 mins before turning down the heat to 165C
Bake for about 30 mins more until a skewer comes out clean
Once done, leave to cool completely on a wire rack before adding the royal icing