Add remaining ingredients and whisk together with a fork until well combined.
Microwave for 1 to 2 minutes. Microwaves vary. The edges set and the center is very moist and shiny, not fully cooked.
Overbaking will result in a dry cake.
Notes
* If you use a flavoured, sweetened protein powder, like vanilla, you most likely won't need the sweetener. You may have to experiment with it, depending on your protein powder brand. Vegan protein powders are often strong tasting and not as sweet, so adjust amounts to your liking!The *best* protein powder is from My Protein. Get 30% off with my coupon code: RACHEL-RDJ9