In a medium saucepan, add the sugar and cook over medium heat until the sugar is melted. Continue cooking, stirring constantly, until the sugar turns a deep amber color being sure to scrape the bottom and sides of the pan to avoid burning. This will take approximately 5-10 minutes. Carefully stir in the butter and vanilla. Continue stirring until completely melted. Slowly add the cream and continue cooking until smooth. Stir in the salt and remove from the heat. Allow the sauce to cool to room temperature and then transfer to a jar with a lid. Store in the refrigerator for up to 2 weeks sealed tightly.

When ready to use, heat slowly in the microwave in 20 second intervals stirring each time until liquid.