Step 1: Preheat the oven to 180 degrees C.
Step 2: Grease and line a 9inch cake pan.
Sift flour and baking powder together and set is aside.
Step 3: Beat together eggs and sugar until light and frothy.
Add in vanilla, oil and milk, beat well until well blended.
Step 4: Now add in flour in 3 to 4 intervals and beat well.
Divide the batter into 2 bowls.
Add in the coco powder in one of the bowls and beat well.
Step 5: Spoon about 3 tbsp of vanilla batter in the center of the pan.
On top of vanilla batter add 3 tbsp of chocolate batter and go on.
Step 6: Donot stir, shake or swirl, the batter will spread by itself as you go on.
Step 7: Serve the cake with some chocolate sauce drizzled or like my favorite way with some fresh whipped cream.