Take the microwave safe dish and grease with oil and sprinkle wheat flour over it and keep aside.
Take wheat flour, baking soda and baking powder and sieve together 2-3 times to mix properly.
Now add sugar powder and mix well then add oil and mix.
Add milk to prepare a smooth better
Add vanilla essence and mix.
Now divide the batter 2 equal parts. Keep one part as it and to the other add coco powder and mix well.
Now take a baking dish and with the help of same size spoons pour both the batter alternately one over the other and after that draw the pattern with the help of toothpick.
Preheat the microwave at 180'c and then cook the cake for 12 mins on convection mode.
Take it out and and serve as desired.