Add all ingredients into a microwave safe mug. To get a cake that will rise to the brim, use an 8 oz mug. You can use a bigger mug as well, it just won't rise as high. Make sure you don't use smaller than 8 oz, otherwise the cake will overflow.
Mix with a small whisk until a smooth batter forms. Make sure you have mashed any avocado pieces. Cook in the microwave for about 1 minute 20 seconds. Your time may vary slightly. Mine took exactly 1 minute 20 seconds on a 1000 watt microwave. Let cake cool a few minutes before eating. Cake is best consumed within a few hours of it being cooked.
Notes
2 tablespoons of mashed avocado is not the same as scooping out 2 tablespoons of avocado and mashing it. You need to mash your avocado first and then measure out 2 tablespoons. I would start with mashing half a medium avocado. To fully mash, you will want to use very ripe avocados making them easier to mash and you want to mash until there are virtually no chunks remaining (otherwise you'll have bits of unsweetened avocado in your cake).
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.