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.
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.
Possible add-ons for this cake: ½ tsp vanilla extract or 1 teaspoon 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 tablespoon 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 Cakefrom Sugar Free Londoner
Note: 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.
- 1 ½ tablespoon coconut flour
- 2 tablespoon peanut butter
- 1 ½ tablespoon powdered sweetener add an additional ½ teaspoon if you have a sweet tooth
- 3 tablespoon double / heavy cream or coconut cream for dairy free
- 1 egg medium
- ¼ teaspoon baking powder
- 1 tbsp dark chocolate, chopped or sugar free chocolate chips optional
- 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.
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.
This is just lush! I’ve been on keto for eight months and found it really boring until I discovered your website. I’m so relieved that I did. Your recipes are awesome and have helped me so much to remain with this lifestyle choice, which I switched to as I have seizures. Super grateful for all the tips, thorough recipes and really good ingredient advice.
Lionel Velez Jr
Can you make it with almond flour?
It should work with around 4 tablespoons of almond flour.
Very yummy! I used a little over half of the called for sugar, used coconut cream and added the vanilla extract as well as 1 tbsp of Reece peanut butter chips and 1.5 tbsp of dark chocolate chips. This was so rich, I think I could have used even less powdered sugar. Definitely enough to share.
Just made this. Best mug cake recipe I’ve made.
Also I forgot to mention in my previous comment I did add the 1/2 teaspoon of vanilla extract. And I used a kitchen scale to measure 10 grams of coconut flour because that's more accurate than 1 1/2 Tablespoons. I think it makes a big difference how much coconut flour you add because it's so absorbent.
Fantastic recipe! SO delicious. I was looking for something more savory, not a dessert, so I omitted the sweetener and the chocolate chips. I substituted 3 Tablespoons skim milk for the heavy cream because that's what I had in the house. (I am not on the keto diet, just grain free). And I mixed the dry ingredients separately from the wet, then mixed them all together and waited about 2 minutes for the coconut flour to absorb more liquid. I cooked it for 90 seconds in a 2 cup (500 ml) glass measuring cup to make sure it didn't overflow. With my modifications, it tasted more like peanut butter bread which was exactly what I was looking for. The texture is AMAZING. It is not greasy nor too eggy like other coconut flour mug cake recipes I've found online. Thank you thank you thank you! This is the first recipe I've tried from your website and now I'm going to try more.
I'm glad you enjoyed the mug cake! Write me a comment when you try something else - I love to hear feedback.
Can I use regular flour?
I think it would probably work with 4-5 tablespoons of flour, depending on how soft your peanut butter is. However, I have not tried it myself.
Very easy! One of the best tasting Keto mug cakes! I added sugarless chocolate chips and pecans… so so yummy
Can this cook in the oven or the air fryer?
Yes, I would go for 180 C electric / 160C fan and about 12 minutes. Then test if it's done.
I found this recipe by searching specifically for recipes that only use coconut flour instead of almond flour, since it's so much cheaper than almond flour. It was really good. And....Although my pet peeve is when people leave comments talking about all the ways they modified the recipe instead of just reviewing it as written, I am doing it myself today simply because the result was so excellent when I changed it.
2 Tbsp coconut flour
1/2 tsp baking powder
2 Tbsp peanut butter
1 Tbsp granular sweetener
3 Tbsp peanut butter
3 Tbsp Almond Milk
Mix, pour into bowl, microwave for 99 seconds. I love this. Coconut flour is so much cheaper than almond flour, and almond milk so much cheaper than heavy cream.
Thanks for writing down your tweaks! I always love seeing how readers adapt the recipes.
You have noted panut butter twice in your recipe 2 Tbsp and 3 Tsp? Is this correct
I don't have Coconut or Almond flour, will this work with Regular flour, I'm not on a keto plan so if it'll work, I'll try it???
It would be a similar amount to almond flour. Maybe a bit less. You'd have to experiment.
Can I substitute coconut cream with coconut butter or plain Greek yoghurt?
I would try greek yoghurt, that should work.
Hi Katrin I have seen in one of your comments somewhere a place in UK where you get your keto baking items etc..
Just wondering would you post it again here.
Looking forward to trying this mug cake .
I buy fine almond flour, allulose and Lakanto monk fruit sweetener from lucky vitamin dot com. You can get Bocha Sweet from Amazon UK.
So happy I discover your website!
First mug cake I ever tried.
This helps to survive my diet.
Thank you sooooo much!
This makes me very happy! So glad you like the recipe!