I have an entire carton of buttermilk of which I needed a 1/2 cup for mashed potatoes and a 1/2 cup for buttermilk biscuits. I decided to use some of it for red velvet cupcakes. Tomorrow I'll make buttermilk waffles to use the rest.
This icing is amazing. I found it on the Confetti Cakes blog (I love her work). I did not use her recipe for red velvet cake but an old family recipe that I prefer.