Ingredients:

2-1/2 cups plain flour 
2 cups sugar 
6 tablespoons unsweetened cocoa powder 
1 tsp. baking soda 
1 tsp. baking powder
1 teaspoon salt
1/2 cup cooking oil
 2 tsp. vanilla extract (essence)
2 tbsp. vinegar 
2 cups cold water

Preparation:

Preheat the oven to 350 degrees F (175 degrees C). Butter and dust with flour a  cake pan.
Sift the flour, cocoa powder, baking powder, soda, salt and sugar together.
 Now add the water, oil, vinegar &  essence to the sifted flour mixture and mix well until smooth.
 Stir the batter in one direction only to make the cake lighter.
Pour the batter into a greased & floured tin.
Bake in a pre-heated oven for 30 minutes, or until the cake tests done. The cake is ready when it bounces back to the touch or a toothpick comes out clean.