Keto Chocolate Peanut Butter Mug cake

A chocolate and peanut butter flavored mug cake studded with chocolate chips. This mug cake is flourless, gluten free, low carb and keto friendly.

Chocolate and peanut butter are one of my favorite combinations. A few months ago, I shared my 3 Ingredient Keto Peanut Butter mug cake. This cake is almost just as easy except that it adds a few more ingredients to give the cake a chocolate flavor.

Mug Cake Cooking Tips

  • Make sure that the egg is completely whisked into the batter. It can sometimes be a little hard to tell because the cocoa powder makes the batter dark. Lift your whisk a few times to check to make sure you don’t have any unmixed egg streaks.
  • This cake rises quite high during cooking so you will need to use a microwave-safe mug that can hold at least 12 oz of liquid.
  • Try to stick to standard shaped mugs. Mugs that are unusually tall/skinny or oddly shaped can cause problems with the cake cooking evenly.
  • Be careful not to overcook the cake. Because microwave cooking is so powerful, even a few seconds can make a big difference. If you feel your cake is not fully cooked, cook it a little longer at 15 second increments.

Update: Since sharing this recipe I’ve also made a Keto Blueberry Mug Cake! Or check out my Keto Lava Cake for Two.

Keto Chocolate Peanut Butter Mug Cake

Prep Time: 5 minutes
Cook Time: 1 minute
Course: Dessert
Cuisine: American
Servings: 1

This easy single serving mug cake is low carb and keto-friendly. It tastes of chocolate and peanut butter, with melty chocolate chips throughout.


  • 3 tbsp creamy natural peanut butter no salt, sugar or palm oil added
  • 1/2 tbsp unsweetened cocoa powder
  • 1 large egg
  • 2 tbsp Swerve granular sweetener
  • 1 1/2 tbsp sugar free chocolate chips or dark chocolate chips


  1. Add everything except chocolate chips into a microwave-safe mug that can hold at least 12 oz of liquid. Whisk with a small whisk until batter is smooth. Make sure batter is evenly mixed and egg is completely incorporated.

  2. Stir in half of the chocolate chips. Sprinkle remaining on top.

  3. Cook cake at full power in the microwave for about 1 minute to 1 minute 15 seconds. Cake is best eaten warm.


  •  I used an 1100 watt microwave. You may need to adjust cooking time and power if your microwave is a different wattage. 
  • Make sure that the egg is completely whisked into the batter. Because the batter is so dark, it can be hard to see unmixed egg streaks. Lift your whisk a few times to check to make sure you don't have any unmixed egg streaks.
  • For the chocolate chips, I used Lily's keto chocolate chips. You can also substitute with other sugar-free chocolate chips or chopped dark chocolate.
  • For the sugar substitute, I used Serve Granular Sweetener.* Other similar granular sugar alternatives should work.
  • *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).

Estimated Nutrition Information is calculated with Lily's keto chocolate chips and does not include carbs from erythritol

Nutrition Facts
Keto Chocolate Peanut Butter Mug Cake
Amount Per Serving (1 cake)
Calories 412 Calories from Fat 288
% Daily Value*
Fat 32g49%
Saturated Fat 7g44%
Cholesterol 211mg70%
Sodium 231mg10%
Potassium 573mg16%
Carbohydrates 14g5%
Fiber 6g25%
Sugar 2g2%
Protein 21g42%
Vitamin A 305IU6%
Calcium 121mg12%
Iron 2.6mg14%
Net Carbs 8g16%
* Percent Daily Values are based on a 2000 calorie diet.
The nutrition information provided are only estimates based on an online nutritional calculator. I am not a certified nutritionist. Please consult a professional nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have. All images and content are © Kirbie's Cravings.

5 comments on “Keto Chocolate Peanut Butter Mug cake”

  1. 5 stars
    This is super cute… I love it! Pinning!

  2. 5 stars
    Very good!  THank you for sharing.    I added 1/4 tsp coconut extract for a little extra flavor.

  3. 5 stars
    I made this tonite. I used Trader Joe’s mixed nut butter instead of pnut butter. Sprinkled a light dusting of erythritol on the top to give it just a touch more sweet. My picky eater son loved it so this recipe is a keeper. It’s so easy how could it not be! Thanks!

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