Heat the oven to 350 degrees. Put cupcake liners in the cupcake pans.
In a mixer bowl, cream the butter and sugar.
Add the eggs, one at a time, mixing well.
In a small bowl, mix the cocoa, food coloring gel and water together to form a paste.
Add to the ingredients in the mixer bowl and blend well.
Stir the flour and salt together and add to the wet ingredients, alternating with the buttermilk. Mix well.
Blend in the vanilla. I
n a small bowl, combine the baking soda and vinegar and then add that to the other ingredients in the mixer.
Fill the cupcake liners with batter, about 2/3 of the way full. The batter will be thick.
Bake for 25-30 minutes or until a toothpick comes out clean. Cool completely before frosting.