Homemade Carmel Syrup

This is a recipe I got from my sister-in-law. It is fabulous!!! It goes great on anything- pancakes, french toast, german pancakes, homemade rolls, waffles, scones etc.....
1 cube butter
1/2 c. buttermilk
1 cup sugar

bring above to a boil
remove from heat and add 1 teaspoon of baking soda and 1 teaspoon of vanilla & a pinch of salt
(you can substitute maple extract for vanilla which is great also)
make sure you use a medium size pan- when you add the baking soda it foams up pretty good.