Hello, I notice that Nigella often suggests using "Instant Royal Icing" for cupcakes and cookies, to which one just simply adds water to make. I live here in the US and have a hard timing sourcing this. As I'm concerned about food safety, I'm hesitant to use raw egg whites to make the icing, and I want something other than a glace frosting! What would be a good alternative to making instant royal icing at home? Thank you!
The UK tends to sell packages of instant royal icing which is, in effect, confectioners' sugar (icing sugar) that has powdered egg white added to it. As powdered egg white doesn't carry any salmonella risk (any traces of salmonella should be killed off during the powdering process) it is safe to use for vulnerable groups. You can buy royal icing mix on-line in the US. N.Y. Cake sell the icing mix and can ship it within the US (see weblink below).
However it is fairly easy to make your own royal icing mix by adding powdered egg white to confectioners' sugar. Often in the US the powdered egg white is sold under the name "meringue powder". Wilton suggest for royal icing that you add 3 tablespoons of their meringue powder to 1 pound (just over 4 cups) confectioners' sugar. Mix the sugar and powder with 5 to 6 tablespoons of warm water (from a recently boiled kettle) and beat with an electric mixer for 7-10 minutes until the icing is thick. Other brands should have instructions for use on the packaging. Meringue powder can be bought at cake decorating stores, on-line and if you are close to a Michael's store then they often sell meringue powder too. The opened packages of powder last a reasonable amount of time if sealed and stored in a cool, dry place.
You could also use carton egg white which is available in most supermarkets and grocery stores. But do check on the packaging that the egg white has been pasteurized. In the UK the Two Chicks carton egg white has been pasteurized so is safe to use in royal icing.