01 -
In a heavy saucepan, melt the unsalted butter and light brown sugar over medium heat, stirring constantly to prevent burning.
02 -
Once melted, whisk in the heavy cream until the mixture is smooth and homogenous.
03 -
Cook the sauce over medium heat for 2 to 3 minutes, stirring continuously until it begins to simmer.
04 -
Remove from heat, then carefully stir in vanilla extract and a pinch of sea salt if using, allowing the sauce to bubble before subsiding.
05 -
Allow the sauce to cool to room temperature; it will thicken as it cools.