Preheat oven to 325 degrees Fahrenheit.
Grease and flour two 8" round cake pans.
In a bowl, mix together the flour, baking soda, cocoa and salt. Whisk together and set aside.
In another bowl, mix together the sour cream, milk, vinegar and vanilla. Whisk well and set aside.
Now in your mixing bowl, mix the butter until creamy.
Add the sugar and whip until fluffy. (About a couple minutes.)
Add the eggs one at a time, mixing after each one, but only just until combined.
Alternately add in the dry and liquid ingredients. Start with ⅓ of the dry mixture, mix just until combined. Add in ½ the liquid mixture, mix until combined, then another third of the dry mixture and mix only until combined. Add in the last ½ of the liquid mixture, mix, then add in the last third of the dry mixture and mix just until combined. Be careful not to over mix here because you'll need to mix in the red food coloring next.
Add in the red food coloring. If you want your cake to be a deep red, add a little more red food coloring. Mix until the food coloring is well incorporated.
Bake in a preheated oven at 325 degrees for about 50 minutes. Start checking at 45 minutes. The middle should spring back when touched and a few crumbs should stick to a toothpick inserted into the center of the cake.
Cover with cream cheese buttercream. (Grab that recipe on the blog.)