In a large bowl, mix together the buttermilk, eggs, red food coloring, vanilla extract until well combined.
In another bowl, sift the all-purpose flour, sugar, cocoa powder, baking powder, baking soda, salt, and whisk until well combined. Add the chopped butter.
Add half of the wet mixture into the dry mixture and mix on medium speed for 2 minutes.
Add the remaining wet ingredients at low speed until combined.
Distribute the batter evenly into the cupcake papers and bake for 15 to 20 minutes or until the cupcakes are springy to the touch.