In a medium saucepan, heat the sugar on medium heat for about 5 minutes. Use a wooden spoon to occasionally stir the sugar, getting to the bottom of the pan. At first the sugar might get lumpy, but will soon melt and start turning into the familiar caramel color. Don't stir too often, you do not want the sugar to crystallize.

After 5 minutes, the sugar should become fully melted. Remove from heat immediately and stir in the butter. The mixture will start to bubble.

Continue to stir the butter and sugar until they melt together completely and start to thicken up.

Pour in the heavy cream and add the sea salt. Use a wooden spoon to stir until everything is combined. Place back on the stove for about 2 minutes, stirring the whole time. Remove from heat and allow your salted caramel sauce to cool down completely.