Use this caramel sauce in our Skillet-Baked Chocolate-Chip Cookie.
In a small saucepan, combine sugar, salt, and the water. Cook over medium heat until sugar is a medium amber color (use strips of paper to test: the paler color is undercooked; the amber hue is just right), about 7 minutes; wash sides of pan with a pastry brush dipped in water to prevent crystals from forming. Remove from heat.
Stir in heavy cream; add butter, and stir until combined. Let cool to room temperature; stir in vanilla.
Sauce can be stored in an airtight container in refrigerator up to 2 weeks. Reheat gently; serve at room temperature.