In a mixing bowl, add oil, curd & castor sugar and mix everything well, without any lumps.

Now keep a strainer over it and add all the dry ingredients like maida, baking powder and baking soda. Strain them and mix everything well by adding water. Mix the dough by using fold and cut method.

Then add vanilla essence and give it a mix. Now divide the batter in 3 equal parts in 3 different bowls. Now add 3 different colour in each bowl as shown below. Mix each one of them & keep them aside.

Now heat a kadai for pre-heating with it's base covered with salt and a stand over it. Cover it and pre-heat the kadai for 5 mins on high flame and then 3 mins. on medium flame.

Now add 1 tbsp of green batter into it. Then pour 1 tbsp of blue batter over it. Then over it pour 1 tbsp of orange batter over it. Then again repeat the same procedure. Continue to do the same until you completely pour 3 of the batter into the cake tin. Tap the cake tin twice gently to remove the air bubbles. Now inserting a toothpick, make some swirls over the batter to get the final design.

Now place the cake tin over the stand. Cover it & bake it on a low flame for about 40 mins. Check the cake with a toothpick, if it comes out clean, then the cake is done. Remove the tin from the kadai. Let it come to the room temperature, then demould it by turning the cake tin, upside down...