In a large saucepan, melt sugar and corn syrup with enough water to look like wet sand (about ¼ cup), then bring to boil over medium heat until the caramel has a deep amber color (about 10 to 12 minutes). DO NOT STIR during this process, but wash down sides of saucepan with a wet pastry brush. Watch it carefully…the caramel will turn dark very quickly at the end!
Once deep amber color is reached, remove from heat and stir in butter (mixture will boil up, so STIR it to keep from bubbling over). Return to heat and stir the butter into the caramel until it is completely melted, about 2 minutes.
SLOWLY add the warmed cream, stirring constantly (mixture will boil up again). Allow the mixture to boil for 1 minute. It will rise in the pan as it boils, so keep stirring!
Continue to simmer, stirring continuously, until a digital thermometer or candy thermometer registers 238°F.
Remove from heat. Cool to room temperature before using (caramel thickens as it cools).
Cover any remaining caramel tightly and store for up to 1 month in the refrigerator. Reheat gently in the microwave or on the stove to desired consistency (and to keep it from separating)
Adding 1 tablespoon corn syrup stabilizes the caramel during browning. You can leave it out, however if the sugar crystalizes during the melting stage, add some water with 1 to 2 tablespoons corn syrup to resoften sugar crystals and recaramelize the syrup.Similarly, adding water at the beginning keeps the sugar from burning if you're not careful. If you leave it out, the caramel will turn amber faster, but you have to be super diligent, swirling the sugar in the pan as it melts.The sugar syrup can go from light amber to a black mess very quickly...keep an eye on it and remove from heat as soon as your desired color is reached.Variations:
Salted Caramel Sauce: add 1 teaspoon salt after you remove the caramel from the heat.
Vanilla Caramel Sauce: add 1 teaspoon vanilla extract after you remove the caramel from the heat.
Salted Vanilla Caramel Sauce: you guessed it...add both the salt and vanilla after removing from heat
Whisky Caramel Sauce: take your caramel sauce to another level of flavor with this boozy version...you'll be glad you did!