Add Nutilight to a microwave-safe mug that can hold at least 8 oz of liquid. Microwave briefly for about 15-20 seconds until it becomes soft and easy to mix.
Add in remaining ingredients. Whisk vigorously with a mini whisk to make sure egg is completely incorporated into the batter. Lift whisk a few times to check for any remaining egg streaks.
Cook in the microwave for about 1 minute and 15 seconds or until the cake is cooked. Let brownie cool for about 15 minutes before eating so that the chocolate flavor can fully develop. If desired, you can replate in a smaller mug for presentation.
Notes
I cooked this brownie in a 1100 watt microwave. If your microwave wattage is stronger or weaker, you may need to adjust cooking time or power.
I recommend using a wide 8 oz mug rather than a narrow one for cooking the brownie because it will shrink slightly after it is done cooking. If you mug is too narrow, the brownie will be awkwardly shaped when it shrinks. I cooked mine in a wide mug and then replated in a narrow one.
For photo purposes, I doubled the recipe so that you can see the cake better. Because this brownie is so rich, it is not meant to be very big. It will only rise about 2/3 of the way in an 8 oz mug.
The brownie is not super sweet. If you prefer something sweeter, you can double the amount of erythritol.
You can substitute erythritol granular with Swerve.
I used Nutilight* for this recipe but you can use another low carb Nutella spread.
*Some of the product links contained in this post are affiliate links. Much like referral codes, this means I earn a small commission if you purchase a product I referred (at no extra charge to you).
The estimated nutrition carbohydrates count excludes sugar alcohols. The net carbs excludes both fiber and sugar alcohols.
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.