Leave to cool for 10 minutes then transfer to a wire rack.
To make the icing, first sift the icing sugar into a bowl. Lightly beat the egg white and add to the bowl.
Beat with an electric whisk until well mixed.
Add orange food colouring, a little at a time, beating between each addition until you get the colour right.
Add lemon juice to loosen mixture, a little at a time.
You're looking for a pouring consistency but not too thin.
Remember, you can always add more lemon juice to loosen, but you can’t remove it!
Place the cooled biscuits on a small rack over a tin to catch the icing drippings.