Preheat oven to 375 degrees.

Line two standard-size muffin pans with baking cup liners.

In a bowl whisk together the cake flour, salt, cocoa, and baking powder to combine.

In a pitcher, whisk together the buttermilk, food coloring and vanilla until blended.

In a standard mixer set on medium to medium-high speed, beat the butter and sugar until light and fluffy, about 5 minuted.

Add the eggs, one at a time. Beating until fully incorporated; scrape down the sides and bottom of bowl as necessary.

Add the flour mixture in portions, alternating with the buttermilk mixture until smooth and just blended.

In a cup combine the vinegar and baking soda, allow to fizz, then fold into the batter by hand.

Working quickly divide the batter evenly among the muffin pan cups and place into the oven immediately.

Bake for 15 minutes, then check center of the cupcakes with a toothpick. If you have a few crumbs clinging to the toothpick the cupcakes are done. If the toothpick comes out with more than a few crumbs, return to the oven for a minute or so, watching closely.

Cool cupcakes in pan on a wire rack until cool enough to handle, about 15 minutes. Carefully lift each from the pan, and set on the wire rack.

Cool to room temperature before icing, about 30 minutes.