Preheat the oven to 350`F.
While the oven is heating mix up the red velvet cupcakes. Sift together the flour, baking soda and cocoa in a medium mixing bowl.
In a large bowl combine the butter, buttermilk, sugar, eggs, red food color, vinegar, and vanilla.
Add in the flour mixture 1/2 cup at a time, pouring slowly.
Beat the mixture with a hand mixer on medium speed for about 2-3 minutes until well combined.
Fill cupcake liners about 2/3 of the way full with batter.
Bake the cupcakes for about 18 to 20 minutes.
Place the finished cupcakes on a cooling rack to cool.