Spray a 13x19-inch pan with non-stick cooking spray (batter may be divided between two smaller pans, just adjust baking time accordingly. If a large pan isn't used, the batter will run over in the oven and burn).
Mix all the dry ingredients together and make a well in the center.
Stir all the wet ingredients together and pour all at once into the well in the middle of the dry ingredients.
Stir just until the dry ingredients are dampened - don't overmix.
Pour batter into pan, spread evenly, and bake for 25-30 minutes for the pan size given.