Preheat the oven to 350°F (180°C). Line two standard 12-count muffin pans with 16 cupcake liners and set aside.
In a large mixing bowl, sift the cake flour and cocoa powder together, then whisk in the baking soda and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using a handheld mixer, cream the butter and sugar together on medium speed for 4 to 5 minutes or until light and fluffy.
Add the egg and mix until fully combined, then mix in the oil, red food coloring, vanilla extract, and vinegar, stopping to scrape down the sides of the bowl as needed.
Mix in the dry ingredients in three additions alternating with the buttermilk, starting and ending with the dry ingredients. Make sure to mix in each addition until just combined and be careful not to over mix the batter.
Evenly distribute the batter between all 16 cupcake liners in the prepared muffin pans, only filling each one about halfway full.
Bake for 15 to 18 minutes or until the tops of the cupcakes spring back when lightly touched and a toothpick inserted into the center comes out clean.
Carefully remove the cupcakes from the pan and transfer to a wire rack to cool completely.