For preparing tri-color marble cake, first whisk together butter and powdered sugar in a bowl.

Add beaten egg to it and whisk again.

Sieve baking powder and flour in another bowl and fold it with the whisked mixture.

Add milk and vanilla essence to it and mix well.

Now divide this mixture into three equal portions.

Mix cocoa powder with 2-3 tbsp of milk and blend it with one portion of the divided mixture.

Blend the red food color with another portion of the cake mixture.

Now coat a baking tray with butter and pour the red colored cake mixture first in the tray, then the plain cake mixture and finally the cocoa powder mixture on the top.

Take a toothpick and simply draw lines in the cake(use your creativity here, you can line it randomly or spirally..it¦s up to you).

Bake it for 1 hour in 160c. Tri-color marble cake is ready.