Preheat the oven to 375 degrees. Sift together the flour, baking cocoa, soda, salt and sugar directly into a 9-inch round or 8-inch square baking pan. In a bowl, blend the oil, water or coffee, and vanilla and pour into the pan. With a fork or a whisk, mix the batter until smooth. Add the vinegar and stir quickly. There will be pale swirls in the batter as the baking soda and vinegar react. Stir just until the vinegar is evenly distributed throughout the batter. Bake for 25 to 30 minutes and set aside to cool. (Serves 8)
From the Moosewood Restaurant Low Fat Favorites, published by Clarkson N. Potter, Inc. 1996.