Use a sieve to sift icing sugar, cocoa powder and cornstarch together into a large bowl.
Add the ground almond and salt.
Stir in most of the egg whites and amaretto until a thick, firm batter is formed. If the batter is too dry add the remaining egg whites.
Dip a small ice cream scoop into the bowl of icing sugar reserved for decorating and then scoop the batter onto the lined baking sheet. This will cover the dough in the sugar to create that snow-capped finish to your cookies. It also helps prevent the batter from sticking to the ice cream scoop!