Preheat the oven to 350°F (175°C). Line muffin pans with paper cupcake liners.
In a medium bowl, whisk together flour, sugar, cocoa and salt. Set aside.
In a large mixing bowl, whisk the egg, vegetable oil, buttermilk, red food coloring, and vanilla extract until well combined.
Add prepared dry ingredients and mix until smooth, about a minute.
In a small dish, mix together baking soda and vinegar. While the soda/vinegar mixture is bubbling, add it to the batter and mix it well.
Using a large cookie scoop, divide the batter into 12 muffin cups. (Fill the cups 2/3 of the way.) Bake for 18-20 minutes, or until inserted toothpick comes out clean.
Cool the cupcakes for 5 minutes in the pan. Then transfer onto a wire rack to cool completely.