Start out by whisking the egg in your mug. Once it's well beat, add in the milk, the corn oil, and the Nutella. Mix well.

Now pour in the chocolate powder, the sugar and the self rising flour. It's very important that you mix this all thoroughly so you don't get clumps of flour in your cake when it's done.

Lastly, once everything is well combined and you have a smooth batter, go ahead and put your mug in the microwave and set it for 2 minutes. Enjoy!