Bring sugar and 2 tablespoons water to a boil in a small saucepan over medium heat, stirring until sugar dissolves. This will take a few minutes
Increase heat to medium-high and cook without stirring, occasionally swirling pan and brushing down sides of pan with a wet pastry brush, until sugar is a deep amber color, 5-8 minutes. Remove caramel from heat.
Add cream and already cut up butter (mixture will bubble vigorously) and whisk to combine.
Let cool slightly.
Drizzle caramel sauce over brownies, cakes, ice cream,etc and sprinkle lightly with sea salt.
Can be refrigerated. Reheat before using.