In a small heavy saucepan blend water and corn syrup over medium heat. Add sugar and salt. DO NOT STIR or sugar will get up sides of pan and possibly create a grainy final sauce. Boil syrup, without stirring but swirling pan occasionally, until golden caramel. Caution, color changes rapidly toward end.

Remove pan from heat and add cream slowly (mixture will bubble up). Whisk until smooth. Cook sauce over low heat, whisking until it reaches 240. Add butter and vanilla, whisk until melted.

* Note: Couple tablespoons of corn syrup in sugar mixture helps avoid crystalization.