1. Add the brown sugar, half and half, butter, and a dash of salt to a medium sauce pan. Heat over medium heat until the ingredients are melted and combined.

2. Reduce the heat to medium-low and cook for 5-7 minutes, stirring constantly, until the mixture is thickened.

3. Add the vanilla and stir well.

Cool slightly and then serve or store in the refrigerator until ready for use. Warm in the microwave for a few seconds to soften.