In a medium saucepan, combine the brown sugar, buttermilk, and butter. Heat over medium-low heat, stirring occasionally, until the butter is melted and the ingredients are combined.
Stir in the baking soda and vanilla extract.
Continue to cook over medium-low heat, stirring occasionally, until the mixture reaches a thick, syrupy consistency, about 10 minutes.
Remove from the heat and let cool before serving.
Interesting Facts
Buttermilk syrup was popular in the American South during the 1800s.
It is a great topping for pancakes, waffles, French toast, or even ice cream.
Adding baking soda helps the syrup thicken and gives it a nice, foamy texture.