Easy Homemade Butterscotch Sauce

Melt the butter in a medium heavy-bottomed saucepan (not non-stick) over medium heat. Add the brown sugar, salt and heavy cream and stir the mixture with a rubber spatula until it's well blended. Bring the mixture to a boil, scraping down the sides occasionally, and boil it for 4 to 5 minutes. Remove the mixture from the heat and stir in the vanilla extract. Transfer the butterscotch sauce to a container to cool. (See Kelly's Notes.)