Preheat oven to 350 F.
In a bowl, mix together all of your mug cake ingredients!
Transfer the batter to one very well-greased, LARGE mug, and sprinkle a few more chocolate chips on top, if desired.
Bake for 18-20 minutes, let cool, and enjoy!
If using microwave, microwave on high for 1 1/2-2 minutes, but please keep an eye on it, as all microwaves are different.