Brown sugar, butter and vanilla make a remarkable, full-flavored sauce that's something like butterscotch, only better.
In a medium, heavy-based saucepan, combine the brown sugar and water. Stir to dissolve the sugar. Cook over high heat, swirling the pan continuously, until the caramel reaches 280°F on a candy thermometer.
Immediately remove the pan from the heat and slowly and carefully pour in the cream (the caramel may sputter). Boil over high heat for 2 minutes, stirring occasionally, to blend. Remove from the heat and slowly whisk in the butter, vanilla seeds, and salt.
Cool slightly before using.
Make Ahead Tips
The sauce can be stored in an airtight container in the refrigerator for up to two weeks or in the freezer indefinitely.