Basic Cupcakes Icing (Royal Icing)
1 egg white
1/2 teaspoon lemon juice
1 3/4 cup icing sugar
The traditional way to make Royal Icing is to beat egg whites and lemon juice together, adding the icing sugar until the mixture holds stiff peaks.
With modern concerns about salmonella from raw eggs, you can either use powdered egg whites or heat the egg whites first to kill any bacteria. With the heating method, mix the egg white and lemon juice with a third of the sugar, heat in a microwave until the mixture’s temperature is 160°F. Then remove from microwave, and beat in the remaining sugar until stiff peaks form. Using the powdered egg whites method, combine 1 tbsp egg white powder with 2 tbsp water. Proceed as you would otherwise.
If the icing is too watery, add more icing sugar until you get the desired forms.