For 4 people
Prepare the royal ice: in a bowl, whisk the egg white with lemon juice and icing sugar
Add icing sugar if the frosting is too liquid. If it is too thick, do not hesitate to add a little lemon juice to improve its texture
After making the contour of the cookies with a solid frosting, you just have to fill with an frosting previously diluted with a few drops of water. Do not hesitate to vary tastes and textures by dying for example your frosting with a little coloring.