Prep: Preheat oven to 350°F (175°C). Grease, line with parchment, and flour three 8-inch or 9-inch round cake pans.
Whisk Dry Ingredients: In a large bowl, whisk together the flour, sugar, baking soda, salt, and cocoa powder.
Mix Wet Ingredients: In a separate bowl, whisk the vegetable oil, eggs, buttermilk, red food coloring, vinegar, and 1 tsp vanilla extract until well combined.
Combine: Pour the wet ingredients into the dry ingredients. Mix on low speed (or by hand) until just combined. Do not overmix.
Bake: Divide the batter evenly between the three prepared pans. Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
Cool: Let the cakes cool in the pans for 15 minutes, then invert them onto a wire rack to cool completely.
Make Frosting: In a large bowl, beat the cold cream cheese and room-temperature butter with an electric mixer until smooth. On low speed, gradually add the powdered sugar until combined. Add the 1 tbsp vanilla extract and beat on medium-high for 2 minutes until light and fluffy.
Assemble: Place one cake layer on a stand. Spread a layer of frosting. Repeat with the second and third layers. Apply a thin "crumb coat" of frosting over the entire cake and chill for 30 minutes. Once firm, apply the final, thick layer of frosting.