Combine buttermilk, sugar, butter, corn syrup, and baking soda in a large pot over medium high heat.
Once it comes to a boil turn the heat back down to low and stir consistently for 5-10 min.
When it looks a golden caramel color remove it from the heat and add the vanilla. At that point try to resist eating it by the spoonful! Enjoy it on your french toast, pancakes, ice cream... or heck enjoy it right from the spoon! It will save in the fridge for up to 3 weeks!