Preheat oven to 350ºF. Spray 2- 9 in. pans with vegetable pan spray.
In a medium bowl, stir together flour, cocoa and salt; set aside. In large bowl, beat butter, sugar and vanilla until light and fluffy. Add eggs and red icing color; mix well. Add flour mixture alternately with buttermilk to butter mixture, beating until well blended. Stir baking soda into vinegar and fold carefully into batter. Pour batter into prepared pans.
Bake 30-35 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pans to wire racks. Cool completely.
To Ice: Spread a thin layer of cream cheese icing on bottom cake layer. Top with remaining layer and spatula ice cake fluffy.