whipping a 4 to 1 mixture of powdered sugar and egg white for 10 or 15 minutes. Royal Icing A given weight of egg whites can’t dissolve more than about double that weight in sugar. Yet royal icing, a traditional decorative material in pastry work, is made by Royal icing is not a simple foam—it’s a combination of a very dense foam and a paste. Much sugar remains undissolved, but it’s so fine that we can’t feel it on the tongue.