Combine the flour, salt, baking soda, and unsweetened cocoa into a large mixing bowl and sift/whisk together.
In a separate bowl, crack open the eggs, and beat them.
Pour the sugar, buttermilk, oil, and vanilla extract into the bowl with the eggs, and mix until everything is nice and creamy.
Slowly combine the wet, ingredients with dry ingredient. Be sure to mix on a low speed!
Once everything is manageable, switch from mixing the cake batter to folding it.
Next, add it the vinegar, and red food coloring.
Fold in until all of the cake batter is red, and there are no streaks.
Spray two 9 inch cake pans with baking spray, OR grease and flour them.
Pour an equal amount of cake batter into each cake pan.
Shake and tap the pans to release any air bubbles, then let sit for 5 minutes.
Bake each cake on 325 F, for 25-30 minutes.
Remove the cakes from the cake pans, and place them on cooling racks.
While the cakes are cooling, make the frosting.
In a large bowl combine the butter, and cream cheese.
Cream the two ingredients together, then slowly adding in the powdered sugar, but only 1 cup at a time.
Add in the vanilla extract, and milk.
Mix until the frosting is nice and creamy
Once the cakes are completely cool, frost them.