In the bowl of a stand mixer cream together butter and sugar until fluffy. Add eggs one at a time, mixing well after each addition. Then add vanilla.
In a separate bowl sift together flour, baking soda, baking powder, salt, and cocoa powder. Add the flour mixture alternating with the buttermilk and vinegar, beginning and ending with the dry ingredients.
Add red gel food color until batter reaches desired shade.*
Fill a lined muffin tin just over 2/3 full and bake at 350 degrees for 20-22 minutes or until a toothpick inserted into the center comes out clean.
Turn onto a clean surface and allow to cool completely before frosting.
*I typically start with 1/4 Tbs and add in increments until it reaches my desired shade of red