This is my favourite go to recipe, mug cake! When I was still working in ad agency, we usually make this in the late afternoon, just to fulfil the sweet tooth hunger. Its so easy that everyone in the office were craving for it and its an easy way to turn the room into Famous Amos - it smells so good. I had a bit of trouble this time because I was baking it using an oven (I usually bake it on microwave). It took more time to be baked in the oven, around 15-20 minutes, depending on your oven. The chocolate bar gave an amazing addition to the cake. A must try, easy melted chocolate mug cake!