In a medium-sized sauce pan stir together 1/4 cup cold water and granulated sugar until combined.
Set over medium-high heat on the stove top and cook 9 -11 minutes without stirring, or until mixture is a deep amber color.
Start checking closely at the 7 minute mark.
Meanwhile, separately warm heavy cream and butter together with sea salt in a small sauce pan over medium heat. (Absolutely do not boil.)
When sugar and water syrup mixture is a deep amber color, turn the heat down to low and slowly whisk in the warm cream and butter mixture. (Bee careful - this is where it will boil up a lot!)
Whisk over the heat until it's smooth a minute or two, then remove from the heat.
Salted caramel sauce will thicken up as it cools.
When sauce is still warm, spoon over ice cream, cake, pie, cupcakes or cookies.
(The salted caramel will become thick when cooled, but it easily re-heats it in the microwave or on the stove top.)
Store extra sauce in an airtight container in the refrigerator, just reheat on low to thin.