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

*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.
4.67 from 9 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, Cholesterol: 186mg, Sodium: 291mg, Potassium: 380mg, 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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267 comments on “3 Ingredient Flourless Peanut Butter Mug Cake”

  1. Honestly, this worked incredible! I really wanted cake but with no flour, and lack of a car I didn’t know what to do! Thank you so much!!

  2. I just tried it but it doesn’t come out like a cake… it look more like a jelly. I tried to put it in microwave for 30 sec more but it still doesn’t look good. I’m sorry this is such a great recipe but can you suggest what may be wrong in this process? Considering the batter is already smooth

  3. Hey, how do I adjust it to high altitude? 

    • sorry i dont have experience with high altitude cooking. I suggest researching cooking forums that usually give some general advice for baking, cooking, for high altitude

  4. Amazing! It tastes great! 

  5. absolutely delicious and incredibly easy!

    add some dark chocolate chips to make it even better 🙂

  6. I notice you have to pb mug cake recipes…which one would you say works best (I will also most likely omit the sugar)?

    • I like them both! this one is a little less fluffy, but more pb flavor. The other one is light and fluffier, but also less pb flavor. hope that helps. Also I’m not sure how it will taste omitting the sugar completely. you can try reducing it, but it’ll likely taste eggy without any sugar

  7. Delicious.. as looking for a quick fix that was a little sweet and warm. I added a quarter of chopped banana and gave it an extra 20 seconds. CanNot believe it worked. Thank you

  8.  what would I do if I wanted to use honey instead of sugar ? Also, I heard that baking soda is good to use with honey, but you say to use  baking powder. 

    • I have not experimented with making this with honey so I don’t know. honey can activate baking soda but I don’t know the ideal amounts without testing it myself

  9. I do not have a microwave…. are there oven variations? Please and thank you.

  10. Was so very easy to make! Looked, smelled, and tasted delicious! I added a few pieces of dark chocolate to the top for a little extra sweetness. Found my new go to recipe. Thanks!!

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

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

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

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

  15. 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 !

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

  17. 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!!!

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

  19. 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.

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

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