My mother found this recipe in the San Antonio Light and made it often when we were young. As a teenager, I baked this one fairly often.
One caveat: Don't substitute vanilla for sugar. Been there. Done that.
In a 13" x 9" pan, sift together:
3 cups flour 2 cups sugar 2 tsp soda 1 tsp salt 6 Tbsp cocoa
Make three depressions in the dry mixture and put in on depression 2 tsp vinegar, in another 2 tsp vanilla, and in the third 10 Tbsp. vegetable oil. Pour over this 2 cups water. Stir it all together, mixing well.
Bake at 350°F for 50 minutes. Doesn't need to be frosted.