Kirbie's Cravings

3 Ingredient Flourless Peanut Butter Mug Cake

photo of a flourless peanut butter mug cake

This easy flourless gluten free peanut butter mug cake is only three ingredients. It cooks in the microwave and is ready in about 5 minutes.

Just like how easy this mug cake is, I’m going to keep this post simple and sweet.
close-up photo of the top of the cake
I’m quite tired. In the past 2 weeks, I’ve traveled out of town three times. And while I’m grateful for all the experiences, I’m also exhausted. I’m looking forward to being in my own home for an extended period of time and going back to my normal routine and back to my regular blogging schedule.
close-up photo of a spoonful of cake
But even in my exhausted state, I can make this five minute mug cake. And you can too.

I actually already have a flourless peanut butter mug cake recipe I really love. But I was playing around in the kitchen the other day and discovered I could create one with just three ingredients.

This cake is peanut buttery, but also light and fluffy. You won’t believe it’s flourless. If you have peanut butter, eggs, and sugar, I urge you to try it now.

Recipe updated with a new video! You can find all my recipe videos on my youtube channel as well.

If you enjoy this recipe, be sure to check out my cookbook* of nearly 100  mug cakes!

photo of the cover of 5-Minute Mug Cakes cookbook

More Mug Cakes


*Some of the 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).

3 Ingredient Flourless Peanut Butter Mug Cake

Servings: 1
Prep Time: 4 minutes
Cook Time: 1 minute
Total Time: 5 minutes
Course: Dessert
Cuisine: American
This easy flourless gluten-free peanut butter mug cake is only three ingredients. It cooks in the microwave and is ready in about 5 minutes.
4.65 from 14 votes


  • tbsp creamy peanut butter
  • 1 tbsp + 1 tsp white granulated sugar
  • 1 large egg


  • Whisk all ingredients into an oversized, microwave-safe mug until batter is smooth and egg is fully whisked in. Microwave for about 1 minute. Let cake cool a few minutes before eating.



Serving: 1mug cake, Calories: 418kcal, Carbohydrates: 26g, Protein: 18g, Fat: 28g, Saturated Fat: 6g, Sodium: 291mg, Fiber: 2g, Sugar: 21g, NET CARBS: 24g

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.

Did you make this recipe?I'd love to see it! Mention @KirbieCravings and tag #kirbiecravings!



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283 comments on “3 Ingredient Flourless Peanut Butter Mug Cake”

  1. My grandsons and I are planning a Zoom session together to make this mug treat. They LOVE p-nut butter. Do you think I should use the baking soda or baking powder version? Thank you for all your great recipes!

    • Hi Toni! The recipe doesn’t need baking soda or baking powder – just flour, sugar, and egg. Hope that helps!

  2. Great 
    Made it with brown sugar-all I had- came out great!
    Wouldn’t be a bad breakfast with fruit 

  3. I love that your recipes have so few ingredients! I am on a very low fat diet and don’t eat wheat.
    Do you have any mug cake or bread recipes that use peanut butter powder?

  4. I followed the directions exactly and it did NOT come out as pictured. When it did not appear to be baking, I ended up adding more time. It eventually baked for 4 minutes (which is too long, I found) and only came up about a third of the way up the mug. What happened?

    • We’re sorry to hear you had problems with this recipe – without knowing more details it’s hard to say what might have gone wrong. One issue might be that the egg was not fully whisked into the batter.

  5. Made it with crunchy PB (no creamy in the house right now) and a little less sugar. Turned out great. Very fluffy! Definitely calls for a glass of milk (if dairy is your thing). Easiest mug cake ever.

  6. At the beginning I had a doubt seeing the head of my mugcake but in fact it was delicious! To do again 🙂

    • I’m so glad you liked it!

      • I follow the keto lifestyle, so I used erythritol instead of sugar and it turned out perfect, quite fluffy and delicious?Topped it while warm with a square of Lindt 85% and blueberries?Thank you for the great and easy recipe?

      • I’m so glad you enjoyed!

  7. This is delicious and tastes like peanut butter cookies.  I put vanilla ice cream on it while it was still warm.  Thanks for the recipe! 

  8. I tried this and it comes out so delicious

  9. it was good but tasted a little bit like an omelet but that might be because I did not mix it well enough?

    • You need to make sure the egg is completely whisked into the batter. It should not taste like an omelet if the egg is completely mixed in.

  10. Would you recommend using this recipe or the one you have w/ baking powder?

    • For me, it comes down to personal preference. The baking powder one is fluffier but the one without it has a stronger pb flavor.

  11. My kids loved this, it was very easy and quick… something they can even learn to do.  They put toppings they like on top like sprinkles, love how it’s gluten free! Very nice to have something to turn to quick. Thanks!!

  12. Really good!

  13. Just madr this and it was delicious! But then your recipes always are!

    After being given a cake in a mug packet from a friend I knew I wanted a quick treat and a mug cake seemed perfect after enjoying the packet one the other week.

    So yummy! And I saw your link about your book for mug cakes so picked up a copy to keep at my sister’s so we can make quick treats when I’m round ?

  14. I was looking for easy tasty simple microwave stuff and I tried this with my 3 year old son it is delicious and soo hassle free and he basically loves that he made a cake =D maybe it’s my microwave but cooked it for a bit more =) thank you!

  15. Would it still bake properly if the mug was placed in an oven?

    • I have not tested it in the oven, but I think it should work. The texture may not be as fluffy as in the microwave though

  16. Can I substitute the PB with Nutella?

  17. Just made this with Swerve instead of sugar and added a tablespoon of Lily’s chocolate chips. Really good!

    • So glad this worked out for you!

    • Just tried this, Where have you been the last five years? I could hug you. Hubby is gluten free and this was a perfect snack! I added soy chocolate chips and topped with a blueberry glaze I had left over. Can’t wait to try your other mug cakes. Thank you for posting!!

  18. This cake was so good I added some baking powder just a little and microwaved it it came out fantastic 

  19. I’m home sick and wanted a little comforting treat. This was perfect! So delicious and easy, thanks for the recipe!

  20. Thank you for the recipe, loved it! Switched sugar for Truvia because my husband and I are on the keto diet and it was a great dessert! Will be making this again! 

  21. Omg! This is delicious! I too swapped stevia for sugar. I drizzled chocolate syrup on top! Yummo!!!!

  22. Tried to make it and it was a gelatinous mess, even though I followed the recipe. I am not sure why other people are getting good results…I will have to try it again.

  23. Just made this 5 mins ago…. Soooo yummmyyyy.

  24. Well I’m not sure if anyone else has done so already but we are in the process of moving so my kitchen is practically packed and already at new house. Stupid move I know but you can make this in a mason jar if you don’t have a mug handy just have to microwave for 2 minutes and I’m assuming it’s bc the mouth of the jar is smaller than a mug. Delicious!!!

  25. Can I use brown sugar instead of granulated white sugar? 

  26. Made this tonight! I used Stevia in replacement of granulated white  sugar , it was delicious !! CAN’T be 3 ingredients to satisfy your sweet cravings, while also being cautious of what you’re consuming! 🙂 thank you for this !

  27. Just tried and put whipped cream on top.itll be my goto since im doing lowcarb

  28. This mug cake was delicious! It tasted just like a peanut butter cookie and I love that it was flourless!

  29. OMG! !!Too good and too easy to be true u r amazing! !!!!!

  30. Is there anyway to make this in the oven??? looks delish! but i dont own a microwave…

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