In a microwave-safe mug, add butter and heat in microwave until completely melted. Only heat a few seconds at a time, swirling in between, so that the butter does not overheat and splatter.
Once butter is melted, add in pumpkin puree and then egg. Whisk vigorously until batter is smooth and no egg streaks remain.
Add in remaining ingredients. Whisk until batter is smooth.
Cook cake at full power in the microwave for about 1 minute 45 seconds to 2 minutes, or until cake is cooked. Let cake cool a few minutes before adding toppings of your choice and serving.
Notes
I use an 1100 watt microwave. You may need to adjust time and/or power if you are using a different wattage.
The cake is not overly sweet on its own so if you do not plan on adding any toppings, you may want to add a little more sweetener to the batter.
The final cake is about the size of a regular muffin or cupcake. You can replate in a smaller mug for presentation.
You can use fresh or canned pumpkin puree. If your pumpkin puree is very watery, drain the excess liquid or dab the puree with a paper towel to remove excess moisture.
The cake is best enjoyed soon after it is cooked. If you are not planning on eating it right away, make sure to keep it in an airtight container so that it does not get dry.
I served the cake with sweetened whipped cream and cinnamon. You can also serve with sugar-free maple syrup or sugar-free chocolate syrup.
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Estimated Nutrition Information does not include carbs from erythritol
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.