In a saucepan, over medium heat, warm the heavy cream. Do not let the cream come to a boil.
In a large pan, over high heat, combine the sugar and water and stir until mixed. Once the mixture has come to a boil, do not stir.
Cook the sugar mixture, without stirring, about 15 minutes or until it turns a dark amber color.
Remove the pan from the heat and whisk in the heavy cream.
Once the mixture stops bubbling, add the butter and whisk until it is melted and the sauce is smooth.
For an even thicker sauce, put the pan over medium heat and simmer another 5-10 minutes. Stop cooking prior to your desired consistency as the sauce will thicken as it cools.
Allow the caramel sauce to cool, transfer to a jar, and seal. The sauce will last 3 days at room temperature and 3 months in the refrigerator.