In a large bowl place the flour, sugar, cocoa, and baking soda, and whisk well to combine. In a separate, smaller bowl, mix together the oil, vanilla, water and vinegar, and whisk well.
Make a well in the middle of the dry ingredients, and pour the wet into it. Whisk just until combined.
This recipe makes one 8" square cake, one 8" round cake or 12 cupcakes. Be sure to prepare your pan before pouring in the batter by either greasing and flouring the pans, using cupcake liners, or lining with parchment.
Bake in a preheated 350 degree oven for 25 minutes.