Put the egg
whites in a bowl and stir lightly with a fork to
break them up.
Add the icing
sugar gradually, beating well with a wooden
spoon after each addition. Add enough icing
sugar to make a smooth, shiny icing that has the
consistency of very stiff meringue.
Beat in the
glycerin, lemon juice and food coloring, if using.
Leave for 1 hour before using, covered with damp
clear film, then stir to burst any air bubbles.
Storing: The icing will keep for up
to three days, stored in a plastic container with a
tight-fitting lid in a fridge.
Icing Consistencies: This recipe
is
for an icing consistency suitable for flat icing
a marzipanned rich fruit cake. When the spoon is
lifted, the icing should form a sharp point, with
a slight curve at the end, known as "50ft peak". For
piping, the icing needs to be slightly stiffer. It
should form a fine sharp peak when the spoon is
lifted.