Sieve together All purpose flour, baking powder and cocoa powder. Keep aside.

In a big mixing bowl add sugar and vegetable oil.

With the help of a hand blender, blend to make a creamy batter. You can also use a whisk to mix.

Add eggs one by one and whisk well to incorporate.

Add vanilla essence and orange zest. Mix well.

Now to this wet mixture add the dry flour mixture.

Mix well with a spatula by cut and fold method. Don't over mix.

Check the consistency of the batter. Add orange juice and mix lightly. The batter should be thick but pouring consistency.

Pre heat oven at 180 degree Centigrade for 10 minutes.

Take a loaf tin of size 10.5 inch by 4.5 inch. Spread a baking sheet at the bottom of the pan. Grease the sides with little oil.

Pour the batter in the prepared tin and tap it 2 -3 times.

Bake it for about 30 minutes or till done. Insert a toothpick in the cake after taking out the tin. If it comes out clean that means the cake is done.

Note: You can use other sized baking tin. But in that case the time of baking may vary. You should monitor continuously after 15 minutes of baking so that the cake doesn't burn or half done.