Grease a microwave safe bowl with either butter or oil.
Mix milk and sugar, mix till sugar is dissolved.
Add oil to this milk and sugar and mix.

Sieve the flour and cocoa powder a couple of times.
Gradually add the milk, oil mix.
Finally add the baking soda, baking powder and lemon juice.
Gently blend and pour into the prepared bowl.
MW the cake for 2 mins. Rest and then again MW for a 2 minutes.
Switch off and let it rest for 5 min. Let the cake cool.
Pour chocolate ganache over it.
Decorate