Preheat oven to 400
Grease an 8x8 cake pan
In a bowl, combine flour, sugar cocoa powder, salt, and baking soda
Stir in the vinegar, vanilla and oil.
Add water and stir to combine
Pour batter into the greased 8x8 cake pan
Bake 26-30 minutes until toothpick inserted into the center of the cake comes out clean
Let cake completely cool before frosting