Each microwave cooks differently, adjust time accordingly! One person made the cake in 1 minute 40 seconds, and another in 1 minute 20 seconds. If you overcook the cake, it may ruin it. Be sure to watch as it bakes.
If you want a neater mug cake, mix the cake batter in a small bowl, then pour the batter in the mug.
You can add mini chocolate chips to the batter for a super rich chocolate cake...or do what I did, throw some on top after you make it, while it's still warm! Mmm, mmm good!