Preheat oven to 350°F (175°C). Grease two 9-inch pans. Line with parchment.
In a large bowl, sift flour, cocoa, baking soda, and salt. Set aside.
In another bowl, beat sugar and oil until smooth. Add eggs one at a time.
Stir in red food coloring, vanilla, and vinegar.
Alternate adding dry ingredients and buttermilk. Mix until smooth.
Divide batter evenly into pans. Smooth tops with spatula.
Bake 25–30 minutes or until toothpick comes out clean. Cool 10 minutes, then transfer to racks.
For frosting, beat cream cheese and butter until fluffy. Gradually add powdered sugar and vanilla.
Spread frosting between cake layers and on top. Decorate as desired.
Chill 30 minutes before serving for best results.