Microwave the butter and sweetener for 30 seconds.
Add the other ingredients and mix well.
Microwave 1 minute.
Notes
Nutrition: This makes 1 serving. The entire mug brownie has 5 NET carbs.Microwave Cooking Times: The power of microwaves can vary. These times are based on an 1100 watt microwave. Decrease or increase as needed for your microwave.To Store: keep leftover mug brownie in the refrigerator for up to 2 days. Make sure they are stored in an airtight container.To Reheat: you can reheat the mug brownie in the microwave for 10-20 seconds. To Freeze: take the mug brownie out of the mug and store in the freezer for up to 2 months. Reheat in the microwave when ready to serve. Notes on Sweeteners: