Spray a microwavable mug with cooking spray and then mix together all ingredients inside mug.
Microwave on high for about 1 minute and 25 seconds. Take out of the microwave and if desired transfer muffin to a plate and add optional toppings. Enjoy!
Notes
*Any kind of milk works. I used unsweetened vanilla almond milk. **Honey works too. This mug cake is only lightly sweet. Add another tablespoon, if you would like it sweeter. ***I also tried this mug cake using Kodiak Cake pancake mix and it worked fabulously! It should work with whole wheat pastry flour, whole wheat flour or all-purpose flour too.