Combine all ingredients in an oversized coffee mug. Whisk well with a small whisk until smooth (make sure you get the flour hiding at the bottom of the mug).
Microwave on high for 1 1/2 minutes and then take it out to check to see if it is done. Cake may be crumbly, but should be fully cooked. If not done, microwave for another 30 seconds. Careful not to overcook it or it gets hard.
You can also make this into two smaller-sized mugs. You can mix the batter all in one mug and then pour half into another mug. Make sure you cook each one individually.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.