Preheat oven to 350°F. Grease the interior of an 8 oz ramekin or similar sized baking dish.
Add egg to a medium bowl. Whisk egg vigorously with a whisk for one minute.
Add in peanut butter and erythritol. Whisk until completely incorporated and batter is smooth. Pour batter into prepared ramekin.
Bake cake for about 16-20 minutes or until cake has risen and when you apply light pressure on the surface it bounces back. Cake should rise above the ramekin during baking but will sink down and shrink once out of the oven. Let cake cool a few minutes before serving. If desired, plate cake in a smaller ramekin or plate. I plated mine in a smaller ramekin. Serve with your favorite toppings like ice cream, whipped cream or sugar-free syrup.
Notes
If you have questions regarding substitutions, please see substitutions section of the post.
This recipe can be made with natural or regular peanut butter. I used natural and found it easier to stir in.
The ramekin I used for baking is an 8 oz ramekin that is 3.75 inches wide.
*This product link is an affiliate link. This means I earn a small commission from qualifying purchases.
If you are on a keto diet, please remember to look at net carbs and not just total carbs. The net carbs count excludes fiber and sugar alcohols (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.