This Keto peanut butter mug cake is a super indulgent, super easy dessert. And it proves the well-known fact that life is just BETTER with peanut butter!
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I love mug cakes, because they deliver almost instant gratification.
There you are, thinking: "Wouldn't it be lovely to eat something sweet right now?" So you stir up a few ingredients and stick it in the microwave.
And less than five minutes later you're tucking into a warm, comforting keto peanut butter mug cake. It's almost too good to be true!
I have a few delicious keto mug cake recipes on my website already - check out this lemon mug cake, my keto chocolate chip mug cake and this cinnamon swirl coconut flour mug cake.
All equally gorgeous, ridiculously simple and delightfully sugar-free. Take your pick according to your craving of the day!
Keto mug cake ingredients
It is possible to make a totally flourless pb mug cake with only peanut butter, egg, sweetener and a little bit of baking powder. This combo was a bit firm for my taste, especially once cooled. (Incidentally, it makes incredibly crunchy peanut butter cookies).
To fluff it up, I added some coconut flour and a good measure of double cream. These additions make the mug cake taste like a REAL, moist cake. Yum.
Which peanut butter to use
Try and source peanut butter that is unsweetened. Good peanut butter really only needs to contain 1 ingredient - peanuts.
Both smooth and crunchy peanut butter work in this recipe - use whichever you prefer!
Carbs in peanut butter
Even though peanuts are technically a legume, they are high in fat and low in carbs - just like nuts. This makes pure peanut butter a great keto food. 1 tablespoon of contains 3.2g net carbs.
Not all peanut butter is keto friendly though. Always read the ingredients when you shop - some brands add sugar or inflammatory vegetable oils.
Which chocolate chips to use
The chocolate chips are optional - the low carb mug cake tastes just as good without. However, we all know that chocolate and peanut butter are a dream team 🙂
I used a chocolate with 90% cocoa solids for my cake, which I chopped. If possible, your chocolate should contain at least 85% cocoa solids.
You can also use sugar free chocolate chips such as Lily's (available in the US). Or you make your own sugar free chocolate chips!
How to make a keto peanut butter mug cake
1.) Choose a tall vessel for microwaving. You want to have at least 3 fingers space at the top. Mug cakes have a habit of rising and can spill over the top.
2.) Mix all ingredients with a fork inside the cup - and microwave. That's it!
3.) Enjoy as is of top with sugar free keto whipped cream, peanuts and shaved chocolate.
Microwave tips
Tip: To avoid a mess, you can pause the microwave to check after about 50 seconds. If necessary, continue cooking the cake in 10 second bursts. This will prevent spillage as you’re giving the cake time to sink back down in between.
Recipe Variations
Possible add-ons for this cake: ½ tsp vanilla extract or 1 tsp cinnamon.
To make this low carb keto mug cake dairy-free, simply use coconut cream in place of the double / heavy cream.
If you prefer cakes with almond flour, use ¼ cup or 4 ½ tbsp almond flour instead of the coconut flour.
Ran out of peanut butter? You can use almond butter or any other nut butter in this recipe.
This PB mug cake is VERY FILLING. Personally, I think it’s perfect for sharing. If you don’t want to spoon from the same cup, simply divide the mix between 2 ramekins.
How to cook this cake in the oven
Don't have a microwave? Simply cook the mug cake in the oven. Use oven proof ramekins and bake at 180 Celsius (350 Fahrenheit) for 10 -12 minutes.
Storing low carb mug cake
You can store this keto mug cake with peanut butter in the fridge for up to 3 days or even freeze it.
If you decide to divide the batter between 2 ramekins and eat one cake straight away and one the next day, I recommend that you refrigerate the second portion as a batter. Then, cook it straight before eating.
Tried this recipe? Give it a star rating below!
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Keto Peanut Butter Mug Cake
from Sugar Free LondonerNote: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary. ***As an Amazon Associate I earn from qualifying purchases.
Ingredients
- 1 ½ tbsp coconut flour
- 2 tbsp peanut butter
- 1 ½ tbsp powdered sweetener add an additional ½ tsp if you have a sweet tooth
- 3 tbsp double / heavy cream or coconut cream for dairy free
- 1 egg medium
- ¼ tsp baking powder
- 1 tbsp dark chocolate, chopped or sugar free chocolate chips optional
Instructions
- Mix all ingredients in a tall glass or cup, using a fork. Fold in the chocolate last, if using.
- Microwave on high for about 90 seconds.
Video
Notes
Nutrition
This post was first published in May 2019. It was updated and republished in January 2021.
This post contains affiliate links. If you click on one of these links and purchase a product, I may earn a small commission, at no extra cost to you. Thank you for supporting Sugar Free Londoner.
Raquel says
Your cake just saved me! I’m on my third week on a low carb diet and I was going crazy! I needed something sweet ! Thank you!
Cecelia Mercer says
Katrin, thank you so much for the peanut butter recipes and especially this recipe. I've printed it so I can make it tomorrow.
Alison Hale says
It’s a great pleasure reading your post. It's full of information. The content of your post is awesome, great work.
Rachel says
Very yummy indeed! I halved the recipe into two separate mugs & I'm glad I did as they are quite filling! I usually have chocolate mug cakes which use almond flour but this was much lighter in texture. Will definitely make this again - thank you!
Colleen McGrath says
Another winner Katrin. So super tasty and quick, we loved it.Thank you for sharing .
Marci Rubinoff says
Sounds incredible and I'd like to try it.
Don't use a microwave.
How long should I bake on convection please?
Thanks!
Katrin Nürnberger says
In a regular oven I'd bake about 12 minutes, then test and see if it's done.
Bava says
I just made this with mixed nut butter that I got at Costco. I do not have a sweet tooth, so I only used 1 tab spoon of sweetener.mi added con and 3 drops of vanilla extract. I got HEAVEN IN A MUG.
Christine See says
This is so easy and so, so good! I did use 1 Tbsp cream cheese and the 1/2 tsp of vanilla extract.
Gwendolyn says
This is my GOTO mug cake!! Add 2 Tbs of warm cream cheese & don’t leave out 1 tsp of vanilla extract. I make mine for 75 secs, it’s PERFECTION❤️
*** top with whipped cream & sliced almonds
Trish says
Just made this on a whim and was very pleasantly surprised!
I made it in a 2 cup Pyrex measuring cup and was able to cook it for the full 90 seconds without stopping. Scooped it right out onto a plate and cut in half for sharing.
Delicious!
Katrin Nürnberger says
So glad you liked it 🙂
Sonya Thomas says
Can you make this with almond flour?
Katrin Nürnberger says
I would try it with 4 tbsp almond flour. You need more almond flour because it absorbs less liquid than coconut flour
Angie says
Absolutely the best mug cake , hands down! Loved it, and will make it again and again. Thank you for your recipe.
paula says
I made these in my DASH and it made 3 waffles; topped with butter and SF syrup and they were SO GOOD!
Katrin Nürnberger says
so glad you liked it!!
Jenny says
I would love to try this but only have peanut flour in the house. Could I somehow use that with a fat to replace the peanut butter? Thanks for any advice you have!\.
Katrin Nürnberger says
That's a good question. I'd do a test by stirring together 1 tsp of peanut flour and 1 tsp of a fat such as coconut oil and see if the result tastes like peanut butter. Then take it from there.
Tess says
Really tasty, and hit the spot! I grated some 90% dark chocolate on top and it was scrumptious!
Thank you for this recipe!
Katrin Nürnberger says
Love peanut butter and chocolate together.... yum 🙂
Nisha says
Would love to try this out but can i leave out the egg & what can it be replaced with
Katrin Nürnberger says
Hi Nisha, you could try a small flax egg - 1 tsp ground flax and 3 tsp water. I haven't tried it yet myself, but that's what I would go for.
Rimal Bumedien says
Genius, love it!!
Katrin Nürnberger says
Glad it hits the spot!
Paula says
Amazing recipe! My main concern was that it would taste too eggy. NOT AT ALL! First keto mug cake recipe I have tried that did not disappoint. I added a little melted cream cheese into the mix. Deelish. Thanks for sharing Katrin!
Bex says
HI! I just have to say that your recipes are unlike anything i have ever tried! I havent been working the past month and thought i should try a low carb lifestyle.I also live in New York City and am very busy so i NEVER cook. It was my resolution to start cooking more and i am amazed that im pretty decent! I found your site, and have literally made almost every main and lots of snaks and desserts- and tonight made the mug cake. Im constantly blown away by how delicious and satisfying your recipes are- my boyfriend doesn't quit believe me when i say they are indeed low carb..
Thank you for all your hard work and the photos and videos- I have rewatched many times over! You have given me confidence in cooking and Im so grateful!
Kindly,
Bex
Katrin Nürnberger says
Hi Bex, what a lovely comment to start the day to! Thanks SO much for your kind words. I'm glad that you agree low carb can be rather delicious!
fani says
absolutely heavenly
i am a cake addict, if i don't like something i say so
this is DELICIOUS!!!!!
Katrin Nürnberger says
Thanks so much for taking the time to comment. I really, really appreciate it 😉
Louise Hill says
Just made this with Almond flour and Almond butter works well. Finished amount could feed a family of six! Maybe I misread amounts - also needed more cooking time.
Katrin Nürnberger says
Good to know it tastes nice with almond butter! It is a filling cake 😉
Brenda says
I don't believe in microwaves due to the belief of damaging food at a molecular level. Have you tried heating this in the oven? I would love to try this!
Katrin Nürnberger says
I haven't, but it should work. I would put it in at 175C / 350 F for about 10-12 minutes.
Andrew says
“2 people sharing”
Ahhahaha, good one!
Katrin Nürnberger says
Sounds like you were hungry!!!! 🙂
Peggy says
I loved this cake! I have made it with Sugar free chocolate chips and again using some blueberries for a peanut butter and jelly vibe. Both were awesome!
Katrin says
I love the idea of using blueberries in it! I’m so glad you like the recipe and that you put your own spin on it
Josh says
Don't normally rate recipes, but this one is absolutely amazing. Do delicious!
Katrin says
I appreciate your comment! Thank you!
Paula says
I made THREE mini waffles in my Dash waffle iron. I dipped the first two in melted butter mixed with sugar free syrup and the third, I lightly toasted and topped with sugar free raspberry jam. It was great both ways!
Katrin says
Both variations sound yummy!!
Lee Turnbull says
After numerous attempts with all sorts of keto low carb mug cakes this was after the first try a winner boom. Thank you for this recipe. Lee. X
Katrin says
That's great! I've got another few mug cakes on my site - just type "mug cake" into the recipe search box at the top of the page - would love to hear what you think of them!
Pamela Donley says
Is it possible to substitute Almond flour for the coconut flour and if so, what would be the ratios?
Katrin says
You'd roughly need twice as much almond flour as coconut flour.
MALLORY BEAVER says
This was delightful! We also made a peanut butter icing with swerve and heavy whipping cream. I felt like I was cheating!
Katrin says
That icing sounds amazing!!!!
Sophia says
Absolutely delicious. I couldn't believe how easy and quick it is to make a cake in the microwave!
Gabriella Romer says
This recipe is amazing! So moist and soft... I've made it three days in a row now 🙂