Stir together all the ingredients in a large microwave safe mug.
Microwave for 1 minute.
Notes
Nutrition: the nutrition facts are for 1 whole mug cake. There are 4.3 NET carbs per serving.Tips: this has a mild peanut butter flavor. To make it more peanut buttery add a small spoonful of straight peanut butter to the center (don't mix it in) before microwaving!To Reheat: you can reheat the leftover mug cake in the microwave for 10-20 seconds. Don’t heat it up too long, or it will become dry and hard. To Freeze: you can make up the peanut butter mug cakes in advance and put them in an airtight container and freeze. They will last 2 months in the freezer. Notes on Sweeteners: