Lightly grease an 8 to 10-ounce microwave-safe mug or ramekin. with cooking spray and then mix together cake mix, water and oil inside.
Add cake mix, oil, and water to the inside of the mug or ramekin and stir to combine.
Microwave on high for 1 minute then check for doneness. Continue cooking in 10 second increments until done.
Remove from microwave and allow to cool for a couple minutes. Add optional frosting and sprinkles, if desired.
Notes
A mix that makes a "moist" cake tends to work best.To lower the fat and calories, the oil can be replaced with applesauce or mashed banana.Adjust water as needed.