Preheat your oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a large bowl, sift together the flour, sugar, cocoa, baking soda, baking powder, and salt. Make a well in the center and add the water, oil, vinegar, and vanilla. Beat until smooth.
Pour the batter into the prepared pan. Bake for 30 to 35 minutes, or until a toothpick inserted into the center of the cake comes out clean. Cool before serving.
Interesting Facts
This cake is also known as a "Texas Sheet Cake" because it is traditionally baked in a large, shallow pan.
This cake is very versatile and can be served as a stand-alone dessert or topped with your favorite frosting.
This cake is perfect for potlucks or other large gatherings, as it can easily be cut into small pieces.