1 cup packed brown sugar
1/2 cup heavy cream
4 tablespoons butter
Pinch of sea salt
1 tablespoon vanilla extract
Melt butter in pot, mix in brown sugar, cream and salt.
Cook over medium-low heat and whisk gently for about 7 minutes
Remove the pot from the heat; add vanilla and return to cook for another minute or so to thicken a bit more.
Pour into a jar and refrigerate.