Mix flour, sugar, cocoa, baking soda and salt in a 9×13 pan.
Make three holes in the flour mixture.
In one put vanilla; in another the vinegar, and in the third the oil.
Pour water over all and stir well.
Bake at 350 degrees F until it springs back to the touch or a toothpick inserted near the center comes out clean – about 25 minutes.
1 stick margarine
1 teaspoon vanilla
1/4 cup milk
Melt margarine and add vanilla and milk. Add powdered sugar until desired consistency – loose but spreadable. This thickens as it cools.
**As a variation, I add a teaspoon of ground cinnamon to the flour mixture and add a cinnamon chocolate buttercream icing to the top.