Put ingredients in the mug in the order given (except choco chips) and stir. Cook in the microwave for 1 to 2 minutes depending on your microwave and how gooey or cake-like you prefer your brownies. Start with 1 minute and then stir - cook an additional 30 seconds at a time till the brownie is exactly like you want it.
Add chocolate chips to the top.
Let cool a bit and let those chocolate chips get all gooey.
Delicious with a bit of ice cream or whipped cream added on top!