1/3 cup (3 ounces) pasteurized egg whites
4 1/2 cups, plus
1 tablespoon sifted confectioners' sugar
1/2 teaspoon lemon juice
In the bowl of an electric mixer fitted with a paddle attachment, beat the egg whites on medium speed until soft peaks form. Gradually add the confectioners' sugar, 1/2 cup at a time, on medium-low speed. Add the lemon juice and beat on medium-high speed until stiff peaks form and the icing is no longer shiny, 6 to 8 minutes.
Use immediately or place the icing into an airtight container. You can keep Royal Icing in the refrigerator for up to 5 days.