Adapted from Dorie Greenspan's Around My French Table
1 cup sugar
2 tablespoons water
1 tablespoon light corn syrup
3/4 cup heavy cream, at room temperature
1 tablespoon butter
1 teaspoon vanilla
Put the sugar, water and corn syrup into a medium saucepan. Cook over medium high heat, swirling the pan, but not stirring until the caramel turns an amber color.
Lower the heat and carefully add cream and butter...standing away from pan to avoid splattering. When bubbling subsides, stir sauce till smooth. Add vanilla. Pour into heatproof jar (I use a Pyrex measuring cup). Cool to warm or room temperature before serving.