I received this royal icing recipe with corn syrup from a professional baker. I prefer to use this instead of a regular royal icing recipe with egg whites. It hardens nicely and is glossy rather than matte, like regular royal icing.
Ingredients:
¼ cup warm water
1 tablespoon light corn syrup
¼ teaspoon almond extract
3 cups confectioners' sugar, or more as needed
Directions:
Stir together warm water, corn syrup, and almond extract in a small bowl until corn syrup and extract have dissolved.
Place confectioners' sugar into a large bowl and pour in corn syrup mixture. Beat with an electric mixer on low speed until royal icing is smooth. Store in a lidded container for up to a week; stir thoroughly before using.