In a small saucepan, heat the heavy cream, stirring to make sure it doesn't burn. Warm cream until it's hot and set aside.

Meanwhile, combine sugar, water, and corn syrup in a medium saucepan with tall sides. Place a candy thermometer on the side, making sure it doesn't touch the bottom. Heat over medium-high, swirling the pan every once in a while, until the candy thermometer reaches 340 degree F. Brush sides of pan with cold water while cooking to prevent crystallization.

Once the caramel reaches 340 degree F, reduce the heat, and stir in the hot cream. It will bubble and spit. Remove from heat, and stir in vanilla extract and salt. Place in a jar, cool, and refrigerate until ready to use. Microwave to rewarm or reheat it over low on the stove.