01 - Preheat oven to 350°F. Grease and flour two 9-inch round cake pans, then line bottoms with parchment paper.
02 - Whisk together flour, sugar, baking soda, salt, and cocoa powder in a large bowl.
03 - In another bowl, mix vegetable oil, buttermilk, eggs, red food coloring, vanilla extract, and vinegar until smooth.
04 - Gradually add wet ingredients to dry ingredients, folding with a spatula until smooth and free of lumps.
05 - Evenly divide the batter between the prepared cake pans.
06 - Bake for 28 to 32 minutes or until a toothpick inserted in the center comes out clean.
07 - Allow cakes to cool in pans for 10 minutes, then turn out onto wire racks to cool completely.
08 - Beat cream cheese and unsalted butter together until smooth and creamy.
09 - Gradually add confectioners sugar, vanilla extract, and salt. Beat until light and fluffy.
10 - Place one cake layer on serving platter; spread with one-third of the frosting. Top with second layer and frost top and sides.
11 - Refrigerate assembled cake for 30 minutes to set frosting before slicing.