Buttermilk Syrup is creamy, rich with brown sugar, buttermilk, and butter, and somewhat reminiscent of caramel. It's pure breakfast heaven when poured over a stack of hot pancakes.
Combine the brown sugar and buttermilk in a medium-sized saucepan over high heat. Whisk or stir to combine and bring to a boil, stirring often.
Reduce heat to low or medium-low and simmer for 3-4 minutes, stirring occasionally, until the sugar has dissolved and the syrup has thickened.
Add the butter and stir to melt. Remove from the heat. Add the vanilla and baking soda. Whisk or stir well to combine. Let cool for at least 10 minutes before serving.
Notes
The syrup will foam and become quite thick and frothy the longer it simmers. If you prefer it without the foam, remove from the heat as soon as it thickens before it has a chance to foam or make it ahead of time and allow it to settle before serving. For what it's worth, we like the foam and it doesn't bother us a bit.