Place racks in oven on the second and fourth levels. Preheat oven to 350 degrees. Grease and flour 2 (9-inch) cake pans. Cut out a 9-inch round piece of parchment paper, and place on the bottom of each cake pan and grease and flour. Cream butter, sugar and eggs in a heavy duty mixer. Combine cocoa and food coloring, and add to the creamed mixture. Mix the salt and vanilla with the buttermilk in a 2 cup liquid measuring cup, and add to the batter alternating with the flour. Mix the vinegar and baking soda in a small bowl (this will fizz). Carefully and gently fold this into the batter. DO NOT BEAT! Divide batter between the cake pans, and bake for 30 minutes or until the cakes spring back when lightly touched. Remove from oven, and cool on racks for 15 minutes. Invert onto racks, remove parchment paper and cool to room temperature

Beat cream cheese and butter together in a heavy duty mixer until smooth and creamy. Slowly add the sugar 1/2 cup at a time, blending between each addition. Mix in the vanilla. Beat for about 5 minutes until very smooth. Spread between layers of cake and on top and sides. Enjoy!! Yield: Sufficient icing for a 2 layer cake