To make the royal icing, put the egg white powder and water in the bowl of a stand mixer fitted with the whisk attachment.

Beat until soft peaks form.

Then add the sifted sugar gradually and beat until the frosting is spreadable and glossy. If the frosting gets too thick you can add a bit of cream, milk, or water to thin.

Keep adding water until it flows smoothly, yet still thick, off the whisk.

Spoon some of the frosting into a squeeze bottle, pastry bag, or baggie if you would like to pipe it around the outline of each cookie.

Then roughly fill in the lines, spreading the icing out with a toothpick or the tip of a butterknife.

Decorate your cookies with sprinkles, etc, while the icing is still wet. It will harden as it dries.