Use this recipe when making our Peppermint Yule Log.
Put 1 1/2 cups sugar, the corn syrup and 1/4 cup water in a small heavy saucepan; cook over medium heat, stirring often, until sugar has dissolved, about 4 minutes. Raise heat to high. Bring to a boil, without stirring; wash down sides of pan with a wet pastry brush to prevent crystals from forming. Boil until syrup registers 230 degrees on a candy thermometer, about 5 minutes.
Put egg whites into the bowl of an electric mixer fitted with the whisk attachment; beat on medium speed until soft peaks form, about 2 minutes. Gradually add remaining 1/4 cup sugar. Reduce speed to low. Carefully pour in hot syrup down side of bowl. Raise speed to medium-high. Mix until completely cool, thick, and shiny, 12 to 15 minutes. Mix in peppermint extract. Use immediately.