Add wet ingredients and mix thoroughly. Be mindful to scrape the bottom edges of the mug for any hidden flour chunks.
Microwave for about 90 seconds. The cake will rise high above the rim of the mug. Try not to open the microwave too soon or your cake will sink. If the cake is still uncooked, microwave in 10 second increments.
Allow the cake to cool before adding a dusting of powdered sugar (optional) and serving.
Video
Notes
Microwave times vary depending on microwave wattage and mug size. This recipe was developed in a 1200 watt microwave and a 12 ounce mug (pictured).