4Step 3: Make the Royal Icing

To make the “glue” that will hold your house together, whip egg whites in a clean bowl until frothy, then gradually add powdered sugar and a teaspoon of vanilla or lemon juice. 

Beat the mixture until it forms stiff peaks. Transfer the icing to a piping bag fitted with a small round tip. Royal icing dries quickly, so keep it covered with a damp cloth when not in use to prevent it from hardening.