To make, ice any cut-out cookies (sugar cookies, gingerbread) with a batch of stiff royal icing (icing sugar + egg whites). Leave the iced cookies to dry for at least 24 hours.

Transfer 1-2 ounces of icing ... onto the cookies, and let them dry for around 5 hours before trying to stack them. For pastel colors, just use less coloring. Check out my unicorno gingerbread ...