In medium sauce pan, combine all ingredients except heavy cream. Stir on medium-high heat til dissolved.
Carefully stir with rubber spatula around outside of pan where sugar mixture is bubbling up side of pan. Continually check temperature with candy thermometer.
As soon as temperature reaches 260 F, remove from heat and carefully add heavy cream. Mixture will boil up to 3x the size. Stir carefully - mixture is hot. Allow to cool before use.