Chocolate & banana zebra cake

Preheat the oven at 170 degrees.
Prepare the baking tin (use round instead of square for better result) by lining it with a butter paper or grease it with oil and dust it all around with plain flour.
Sieve together the plain flour, baking powder and baking soda.
In a mixing bowl mix the sugar and the oil well. Add vanilla essence, eggs and gently beat the eggs to incorporate them well.
Add the yoghurt and mix it well but ensure that you do not over beat the batter.
Gradually add the flour mix and incorporate it well into the wet batter. Once done, divide the batter into two equal portions.
Mash the banana and add a dash of lemon so that it does not blacken. (Do not mash it earlier coz it may lead the banana to change its colour)
To one portion add the cocoa powder and to the other add the mashed banana.
Mix each one of them them well into the respective batters.

For Layering:
Pour in 3 tbsp of the banana batter in the centre of the tin. Do not wait for it to spread. Immediately on top of the banana batter add the chocolate batter. Keep repeating the process by adding each batter on top of the other till the whole batter is over. Do NOT try spreading out the batter. Each spoon of batter added on top will push the previous layer towards outside.

Bake the cake at 170 degrees for about 45 minutes or till a tooth pick inserted in the cake comes out clean.