In a large bowl mix together oil and sugar. Add eggs and vanilla essence and stir vigorously until well blended.
Carefully add cocoa powder with the baking powder and flour and mix well.
Grease and flour a 20× 20cm baking pan and pour batter into the tin, using a spatula to make sure you clean the bowl.
Bake for approximately 15 minutes or until finished. A cocktail stick inserted in the centre should come out with a few very slightly moist crumbs on it. That means your brownies are done, but still have that gooey, fudgy texture.
TIP: Chocolate brownies are yummy hot or cold, and can be served as they are or with some vanilla ice-cream.
Putting the brownies in the fridge will keep them fresh for up to a week...if they last that long! They can also freeze well.