Cobine the sugar and water in a saucepan over high heat. Bring the mixture to a boil and cook until the mixture reaches 115 degrees F, the soft ball stage on a candy thermometer. Using a mixer, fitted with paddle, beat the egg yolks. With the machine running, slowly add the syrup. Beat until the mixture is thick and cool, about 5 minutes. Beat the butter well in a mixing bowl. Add the butter, a tablespoon at a time to the egg-syrup mixture and beat well. Add the caramel sauce and beat well. Remove the frosting from the mixer.
Yield: 2 1/4 cups