Ingredients
Unsweetened cocoa (3 tbsp), unbleached all purpose flour (1 ½ cups), baking soda (1 tsp), sugar (1 cup), vanilla (1 tsp), vegetable oil (5 tbsp), vinegar (1 tsp), cold water (1 cup) and salt (1/2 tsp).

Method of preparation:-
Take a large mixing bowl, mix flour, cocoa, salt, soda and sugar in it. Mix all these ingredients properly and then make three wells in it. Put vinegar in one, vanilla in another and oil in the third well. Then pour cold water in it and mix it until the mixture gets moistened. Take a pan of 8*8-inch and then pour the mixture into the pan. Place the pan in oven and bake it for about 25 to 30 minutes at 350 degrees F. Bake it until it springs back when you touched it lightly. Then take out the pan from oven and keep it to cool.