Raw egg whites can be a fiddly cocktail ingredient, not to mention one that some people are uncomfortable with using. Made with pasteurised egg white and sugar (so be sure to dial back or omit other sweet/sugar ingredients in your recipes), this Giffard Syrup makes life much easier.
Simply dry shake (i.e. don't put the ice in yet) your cocktail ingredients - including the syrup - vigorously in your shaker first, before shaking again with ice (just as you would with normal egg white) then strain and pour for the desired texture and foam.
Once opened, consume within 3 weeks.