Preparation In a 1 1/2-quart heavy saucepan bring sugar, corn syrup, and water to a boil over moderate heat, stirring until sugar is dissolved. Boil mixture, without stirring but swirling pan occasionally, until a golden caramel. Remove pan from heat and add butter, vinegar, and a pinch salt, swirling pan until butter is melted. Add cream and vanilla and simmer, stirring, 1 minute (sauce will be a golden brown). Cool sauce to room temperature (sauce will thicken as it cools). Sauce keeps, covered and chilled, 3 weeks. Serve sauce warm or at room temperature.