Kirbie's Cravings

Flourless Peanut Butter Mug Cake

photo of a spoonful of Flourless Peanut Butter Mug Cake
The other day my brother told me he is sick of my mug cake posts. I’m not tired of them yet though. Hopefully you aren’t either. I love that they are fast, especially since I haven’t had time to do a lot of baking. And the one serving size is perfect because nothing gets wasted.

I’ve made a flourless nutella mug cake and a flourless chocolate cake. So the other day I decided to try making a flourless peanut butter mug cake.

Surprisingly, the flourless peanut butter mug cake rose quite high when cooking in the microwave. The other flourless cakes were much more dense. It almost looks like a regular peanut butter mug cake, except there’s no flour.
Flourless Peanut Butter Mug Cake
The cake is very moist and is perfect for peanut butter lovers. And as a bonus, I have another gluten free recipe to add to my collection.

If you enjoy mug cakes, you can view my whole mug cake series here.

close-up photo of a spoonful of cake

Flourless Peanut Butter Mug Cake

Servings: 1
Prep Time: 4 minutes
Cook Time: 1 minute
Total Time: 5 minutes
Course: Dessert
Cuisine: American
This cake is very moist and is perfect for peanut butter lovers. 


  • 2 tbsp peanut butter
  • 1 tbsp granulated sugar
  • ¼ tsp baking powder
  • 1 tbsp heavy cream
  • 1 large egg


  • Mix all ingredients into a mug. Stir with a small whisk or fork.
  • Microwave for about 1 minute. Check on the cake. If not done, cook for an additional 15-30 seconds.


Serving: 1mug cake, Calories: 350kcal, Carbohydrates: 19g, Protein: 13g, Fat: 25g, Saturated Fat: 8g, Sodium: 216mg, Fiber: 1g, Sugar: 15g, NET CARBS: 18g

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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29 comments on “Flourless Peanut Butter Mug Cake”

  1. Even though this is not a ‘dog treat’ recipe, I did make this for my dog and me to share! I omitted the sugar and used natural peanut butter. I ate 3/4 of this and my dog had the rest. I drizzled a little bit of honey on my share. It was a cold and snowy day here today and this was a warm treat for the two of us! Thanks for the great recipe! Will be making this again!

  2. Mine didnt rise to well. maybe i did not use enough baking powder. ended up quite dense . but it’s ok. gonna try again later. just stumbled across mug cakes. love them!

    • Hmm, I would definitely check your baking powder because this cake should rise quite a lot, especially when it is cooking. Also are you using commercial type pb as opposed to natural/homemade? The natural stuff isn’t as creamy and doesn’t work as well. Also make sure you add an entire large egg. You might also need to cook longer? if your microwave isn’t powerful enough, it may need longer in there. hope this helps!

  3. Made this today for dinner… Turned out as more of a sweet peanut butter biscuit. Not sure quite why it turned out that flat as it almost expanded over the rim of my mug. Must have something to do with the eggs not being thoroughly whipped. Will try again, but will whip the eggs separately and slowly add in. On a better note, it was extremely good.

    • Hmm that is weird. It may be the egg like you suggested. Or maybe you need to check your baking powder? Though if it expanded while cooking it sounds like the baking powder is working right

  4. Hey Kirbie, are there any substitutes for heavy cream? Thanks! P.S I will never be bored of mug cakes! I actually made a homemade mug brownie mix and gave it as gifts in a mason jar. So cute!

  5. I finally found out why this didn’t work well for me- high altitude! It rose really high, almost to the point of spilling over, so I added cocoa powder to make it into more of a batter.

  6. I fudged around with this (because I never ever ever use heavy cream, so didn’t have any of it on hand T_T) and used melted butter and a splash of milk instead. Came out quite nicely; not sure if it’s how it’s supposed to be like, but I thought it was still delicious hehe.

  7. I made this tonight with 2% milk because I had no heavy cream on hand. I also used crunchy peanut butter. While it doesn’t look that appealing, the taste is ok. I added a little bit of cocoa and hoped it would be like peanut butter chocolate but its just peanut butter.

  8. uggggggg! my friend moze n i tryd this recipe and it ended up tasting like scrambeled eggs-_-

    • It sounds like you didn’t mix all the ingredients together thoroughly before cooking it. If the egg is completely mixed in with everything else, it wont cook like scrambled eggs

  9. Oooh I wanna make like all of these mug cake recipes, but we’re always missing ingredients. I know what I’m buying with my birthday moneyy.

  10. ChrisB: I will be trying this recipe soon with Almond Milk ( I have an allergy to dairy as well). I will let you guys know how it goes!

  11. Better late than never to have happened on your web site for the mug cakes. The possibilities are endless, a recipe book might be indicated, but the mug cakes are PERFECT for a sweet tooth without going overboard, suits ALL ages.

  12. OOPs… I meant *no cream* instead of no butter. LOL

  13. Wondering if this would be okay using sunflower butter and no butter??? Allergies to peanuts and dairy…

  14. I’m definitely not tired of them! I plan to use your mug cake recipes if I become an RA next year. 😉

  15. You should write a cookbook about mug cakes!!

  16. Ahhh you’re killing me with these mug-recipes! I want to make them so bad… But I don’t have a microwave 🙁 Any way I could make these in the oven? 😀

    • I’m sure it’s possible to make in the oven but I would worry about the mug breaking. Also it would end up taking a lot longer..

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