Preheat oven to 350°F. Carefully line cupcake pan with cupcake liners. Sift together the dry ingredients-flour, cocoa, baking soda, and salt. In another bowl combine the buttermilk, food color, vinegar and vanilla. In the bowl of a stand mixer fitted with the paddle attachment, cream the oil and sugar on low speed, then beat on medium for 2-3 minutes. Beat in the eggs, one at a time, beating well for 2-3 minutes, scraping down bowl as needed. Add the dry ingredients alternating with the buttermilk mixture in thirds. When everything is blended and smooth, continue mixing on low speed for 2 minutes. Use an ice cream scoop and fill the cupcake liners almost full. Bake for 20-22 minutes. Cupcakes are done when they feel firm to a gentle touch on top-they should spring back. Remove from oven and cool completely on metal racks before frosting. The buttercream icing recipe can be found with the Cocoa Cupcakes recipe.