Preheat oven to 350°F. Spray a 10-cup bundt pan with baking non-stick spray. Spray really well!
In a large mixing bowl, sift the flour and cocoa powder together. Add the sugar, baking soda, baking powder, and salt.
3 cups All-purpose flour, 1/4 cup Unsweetened cocoa powder, 1 3/4 cups White granulated sugar, 1 tsp Baking soda, 1/2 tsp Baking powder, 1 tsp Salt
In a separate bowl, mix the oil, buttermilk, vinegar, eggs, vanilla, sour cream, and red food coloring. Mix until it is combined and bright red.
1 cup Oil, 1 1/4 cup Buttermilk, 3/4 tsp White vinegar, 3 Large eggs, 2 tsp Pure vanilla extract, 1/4 cup Sour cream, 1 1/2 tsp Red food coloring
Pour the wet ingredients into the dry. Mix until just combined.
Pour batter into the bundt pan. For a 10- cup bundt pan use 7/8 of the batter. For a 12-cup bundt pan, use all of the batter.
Bake for 40-50 minutes. The cake is done baking when a toothpick inserted comes out clean. Let the cake sit in the pan for 10 minutes. Then, transfer to a cooling rack.
Allow cake to cool completely. Then, make the glaze.