Preheat oven to 350 F / 175 C. Grease and line three 6-inch, or 3 7-inch cake pans.
In a large bowl, whisk together 1 cup vegetable oil, 2 eggs, 1 cup buttermilk, 2 tsp vanilla extract, and 1 tsp white vinegar.
Add 2 cups of granulated sugar and whisk for 30 seconds to help dissolve the sugar.
Mix in 2 tsp cocoa powder, 1 tsp salt, 1 tsp baking soda, and 1/2 tsp baking powder. Whisk until no clumps remain.
Add a squirt of red gel food coloring and mix until the batter is evenly colored a deep shade of red. Then mix in 2 1/2 cups of flour in two installments.
Divide the batter evenly between the prepared pans and bake for 27-30 minutes.
Remove pans from oven, and allow them to cool in the pans for 10 minutes. Carefully flip the layers out of the pans, and place them on a wire rack to finish cooling.
Level the cake tops with a serrated knife once they're fully cooled. Place the cake tops in a bowl and use a fork to crumble them. Cover the bowl with plastic wrap and set aside.
If you make these cake layers in advance and freeze them, let them thaw for about 15 minutes before making the cake. The cake layers should still be slightly cold to the touch, which will make it easier to assemble the cake.