Kirbie's Cravings

Keto Blueberry Mug Cake

A light and fluffy blueberry cake that is also low carb and keto-friendly. This easy cake cooks in the microwave and is ready in about 5 minutes.

close-up photo of a keto blueberry mug cake

This blueberry-studded mug cake is perfect for summer. It starts with a light and fluffy vanilla cake and is mixed with fresh blueberries. You can also use other berries like strawberries or blackberries.

Coconut Flour

Unlike my Low Carb Snickerdoodle Mug Cake, this cake uses coconut flour. Normally, I like using almond flour in my baked goods. However, coconut flour is needed for this recipe because coconut flour is highly absorbent, resulting in a thicker batter. If you try to add blueberries to an almond flour batter, the berries will fall right to the bottom.
close-up photo of a spoon scooping some blueberry cake

Mug Cake Tips

  • Make sure to carefully measure out the coconut flour. Coconut flour is highly absorbent so adding even a little too much can make the batter dry.
  • This cake rises quite high while it cooks and then will sink back down. I like to cook mine in an oversized mug and then plate it in a smaller mug.
  • The cake is best consumed soon after it is cooked.
  • You can top the cake with powdered swerve.

overhead photo of a blueberry mug cake

If you you’re looking for more keto mug cakes you might like my Keto Peanut Butter Chocolate Chip Mug Cake, too.

Keto Blueberry Mug Cake

Servings: 1
Prep Time: 4 minutes
Cook Time: 2 minutes
Total Time: 6 minutes
Course: Dessert
Cuisine: American
A light and fluffy vanilla mug cake studded with blueberries. This cake is also low carb and keto-friendly.
4.83 from 17 votes


  • 1 tbsp unsalted butter melted
  • 2 tbsp heavy cream see note for substitutes
  • 3/4 tsp vanilla
  • 1 large egg
  • 2 tbsp coconut flour
  • 1 tbsp erythritol sweetener granular
  • 1/4 tsp baking powder
  • 6-8 fresh blueberries


  • In a microwave-safe oversized mug, add all ingredients except blueberries.
  • Mix with a small whisk until batter is evenly mixed. Gently place blueberries on top.
  • Cook cake in the microwave at full power for about 1 minute and 40 seconds. Allow the cake to cool a few minutes before eating.


  • I use an 1100 watt microwave. You may need to adjust time and/or power if you are using a different wattage.
  • The cake works best with heavy cream but if you don't have heavy cream, you can use coconut cream or whole milk. Your cake won't be as rich and fluffy using regular milk but it will still work.
  • I used So Nourished Erythritol Sweetener Granular.*
  • Erythritol sweetener granular can be substitued with swerve granular or similar granular sweeteners.
  • This cake rises quite high while it cooks and then will sink back down. I cooked mine in a 16 oz mug and then plated it in an 8 oz mug.
  • *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).
  • Estimated Nutrition Information does not include carbs from erythritol


Serving: 1cake, Calories: 361kcal, Carbohydrates: 11g, Protein: 10g, Fat: 30g, Saturated Fat: 18g, Sodium: 124mg, Fiber: 5g, Sugar: 2g, NET CARBS: 6

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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Recipe Rating

60 comments on “Keto Blueberry Mug Cake”

  1. Please help! What is swerve?
    Greetings from Sweden!

  2. Loved this. For me it’s a two serving muffin rather than single. Altho if on my own, I could eat the whole thing! ?

  3. I just made this and it is delicious. Used swerve brown sugar and it turned out great. Will be making this again!

  4. For those of us that don’t have a microwave, how many minutes at what temp can we bake this in a toaster oven or regular oven? Thanks!

  5. This turned out really good! Next time I will fold the berries into it, rather than leave them on top. A recent diagnosis of type 2 diabetes is changing my eating habits. This recipe fit in very well!

  6. Wonderful!!! Perfect!!! Light and fluffy!

  7. This is by far the best blueberry muffin I have made. Thank you for sharing

  8. One of my all-time favorite keto recipes! I always make this when I’m craving a keto cake. super moist and fluffy with absolutely no eggy taste.

  9. Tried this sweet treat today. I liked the simplicity of the mug cake. I substituted the heavy cream for coconut cream. Was wonderful treat.

  10. It turned out surprisingly amazing! I’m always nervous about trying mug cakes that require a whole egg because I worry it might taste eggy… but not this one! This was absolutely fantastic, super moist and fluffy, and pretty much tastes and feels just like a real cake. satisfied the sweet tooth haha! I think it might need just a little bit more blueberries because it it was a bit empty… but I guess that’s just to keep it more keto-friendly.
    Thank you so much for this perfect recipe! definitely going to try more of your recipes soon!

  11. Hello, can I make this in an oven? 

  12. I just made this and wholy moly it is good. I will try it again…Maybe add some lemon flavor too. I was so hungry and this was perfect to have while enjoying a good read. Thanks for sharing your talent.

  13. I used swerve sweetener and used cream cheese instead of sour creme and it was absolutely DELICIOUS?

  14. Oh thank you. Was craving a sweet breakfast and this is amazing. Delicious, and quick!

  15. This is one of the best keto mug cakes I’ve made! I’ve come to realize I like them made with coconut flour much better than almond flour. Of course that is just my preference. Such a treat!

  16. That was great. Made a very large serve which was delicious with some whipped cream. As with another reviewer, my blueberries didn’t sink so next time I will stir them through.

  17. This was a great recipe! I added about 1 tbsp of lemon juice to the cake batter mixture. It turned out perfectly baked at 1 min 40 seconds and was still so moist. I then stirred 1 heaping tbsp powdered monk fruit into 1 tbsp lemon juice and poured the glaze over the top of the hot cake. YUM!!! Even my 1/2 keto kiddos loved it!

  18. Great easy recipe and tastes very good indeed. I made it with swerve and with a 1000w microwave and used the time you suggested and it came out cooked I think lol. I’ve never used coconut flour before…it has a coconut flavor and not quite a flour texture but it was pleasant.

    I’ll definitely make this again, thinking to try adding banana extract to see how it comes out.

  19. My first attempt at making the keto blueberry mug cake didn’t quite come out as expected. ? I carefully measured out 2 tbsp of coconut flour EXACTLY as noted in the recipe! I have a 1000w microwave, so I went 2 minutes. My cake was dense and not so moist. So, I moved it to a small plate, cut into thirds, and generously topped with heavy whipping cream I whipped at home while the cake was still warm. Maybe 2nd try is a charm…

    • It sounds like you may have overcooked the cake. Especially since this was your first time making it, I would recommend sticking with the time I provided and then increasing in small increments if needed. There are a lot of variables that can affect cooking time, including the mug material, temperature of batter and microwave wattage. The difference between 1000 watts and 1100 watts is very little, around 10 seconds. But when cooking a mug cake 10-15 seconds can be the difference between cooked and overcooked.

  20. My I ask… This will be my first time making a mug cake… What size mug should I use??? Thank You…

  21. Tastes like a cake!

  22. Loved this. Just started my keto journey and this was really good. Also added cream cheese on top and it was delish!

  23. This is soooo yummy. I have a hard time waiting for it to cool so I can eat it

  24. Good blueberry muffin substitute. None of my blueberries left the top though. Next time I will stir half in and leave half on top. I used half in half and granulated stevia.

  25. Loved it!  Nice and fluffy. Perfect for breakfast!

  26. I love this one. I add more blueberries and a little cream cheese with monk fruit sprinkled on top. 

  27. Much nicer than I thought it would be! Made with coconut cream and an ancient 700 watt microwave so almost trebled the cooking time. Lovely and fluffy!

  28. I love this recipe but I do not have a microwave oven. Can you give directions for using a regular oven? Thanks