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 with gems.