Use this simple icing to frost Moist and Boozy Fruitcake with Rum and Port from food writer Melissa Clark's "In the Kitchen with a Good Appetite" cookbook.
In a medium bowl, whisk together egg whites and lemon juice until frothy. Whisk in confectioners' sugar and beat until smooth. Beat in food coloring or almond extract, if desired. Use immediately.
Raw and undercooked eggs should not be consumed by young children, pregnant women, or anyone else whose health is compromised.