Kirbie's Cravings

Coffee Mug Cake (Keto, Low Carb)

This single serving coffee-flavored mug cake is keto-friendly, low carb and gluten-free. It cooks in the microwave in less than 2 minutes.
photo of a coffee mug cake

I love coffee and coffee-flavored desserts, which is why I created this cake. The cake comes out super moist and fluffy, with a strong coffee flavor. I topped it with a dollop of whipped cream.
close-up photo of a spoonful of coffee cake

Ingredient Tips

  • I used erythritol granular to sweeten the cake but other granular sweetener substitutes should also work.
  • This cake uses espresso powder to give it its coffee flavor. Espresso powder is not usually used for drinking and used almost exclusively for baking. You can find it on Amazon and stores that carry specialty baking ingredients (King Arthur Flour, Sur La Table, etc). Do not substitute with instant coffee because instant coffee is not as concentrated and will not dissolve the same. Liquid coffee is also not a good substitute because it will change the texture of the cake and not give the cake enough coffee flavor.

Cooking Tips

  • Whisk the batter together with a mini whisk. Make sure to thoroughly whisk the batter before cooking. You don’t want any unmixed egg streaks because then your cake will taste eggy.
  • Use a microwave-mug that can hold at least 12 oz of liquid. The cake will rise quite high during cooking before it settles down once it’s done cooking. If you want a prettier presentation, you can always replate the cake in a smaller mug after it is done cooking, which is what I did for this post.

overhead photo of a coffee flavored mug cake with a spoon

Coffee Mug Cake (Keto, Low Carb)

Servings: 1
Prep Time: 5 minutes
Cook Time: 1 minute
Total Time: 6 minutes
Course: Dessert
Cuisine: American
A single serving coffee flavored cake that is low carb and keto-friendly. This cake cooks in the microwave in less than 2 minutes!
5 from 3 votes


  • 1 tbsp unsalted butter melted
  • 1 large egg
  • 3 tbsp superfine almond flour
  • 1/2 tsp baking powder
  • 1 1/2 tbsp erythritol sweetener granular
  • 1/2 tsp espresso powder
  • 1/2 tsp vanilla


  • In a microwave-safe mug (that can hold at least 12 oz of liquid), add all ingredients. Mix with a small whisk until batter is smooth.
  • Cook cake in microwave at full power for about 1 minute 20 seconds. The cake will initially rise quite high while it cooks before settling back down. You can replate the cake in a smaller mug for presentation (which is what I did for the photos in this post). Be careful to not overcook the cake because that will cause the cake to harden as it cools. Top with your favorite frosting or syrup. I topped mine with some whipped cream. Allow the cake to cool a few minutes before eating.


  • I cooked my cake in a 1100 watt microwave. If your microwave wattage varies signficantly, you may need to adjust cooking time. I find that if it only varies by 100 watts, then the cooking time usually remains the same.
  • I used King Arthur Flour espresso powder.*
  • I used So Nourished Erythritol Sweetener Granular.*
  • *This product link is an affiliate link. This means I earn a small commission from qualifying purchases (at no extra charge to you).
  • The estimated nutrition carbohydrates count excludes sugar alcohols. The net carbs excludes both fiber and sugar alcohols.


Serving: 1cake, Calories: 308kcal, Carbohydrates: 6g, Protein: 6g, Fat: 27g, Saturated Fat: 9g, Sodium: 66mg, Fiber: 2g, Sugar: 1g, NET CARBS: 4

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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5 from 3 votes

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Recipe Rating

8 comments on “Coffee Mug Cake (Keto, Low Carb)”

  1. Hello, wondering if egg whites could be used as a leaving agent in place of baking powder as I have a dietary restriction?

  2. I tried this today with 3/4 tbsp of coconut sugar and decaf instant coffee. It was sooo good!

  3. This recipe was really interesting for me. I tried it last night and it was so good.

  4. Could you make this without the espresso coffee & have a nice vanilla cake? I assume the espresso coffee has caffeine?