This Keto Blueberry Mug Cake is a delicious keto dessert or breakfast that you can make in just 1 minute in the microwave.
When you’re craving something sweet and familiar, like a blueberry muffin, but you don’t have time to mix up all the ingredients and wait for them to bake, this recipe will definitely hit the spot.
This blueberry mug cake is light and fluffy, without all the carbs and it’s just one serving, so you won’t have tempting left overs.
When you’ve been on a keto or low-carb diet for a while, it’s easy to almost forget about your cravings for sweets, but once in a while it hits you and you just need to satisfy the craving so you can move on. This keto mug cake does that for me.
It’s super easy to make – taking just 1 minute in the microwave. In a total of just 6 minutes, you can have a beautiful dessert (I actually eat this for breakfast!) that’s just one serving.
» Here are a few more keto desserts to try.
How Many Carbs Are in Keto Mug Cake?
If you’re wondering about the carbs, you’ll be happy to hear that this blueberry mug cake has just 4 net grams of carbs.
That means you can eat the whole thing and not feel guilty about it. You only have to save a little room in your daily carb count for this treat.
How to Make a Blueberry Mug Cake
To make a mug cake, you’ll need a microwave-safe mug that’s at least 10 oz. I use my regular coffee mug and it has plenty of space for the cake to expand. You can also use a 10 oz or larger ramekin.
Spray the inside of the mug with cooking spray or rub a little coconut oil inside the mug to prevent sticking.
You can use coconut flour instead of almond flour, but the batter might turn out just a bit dry, so you may need to add a teaspoon of water to the batter to smooth it out.
I personally prefer to use almond flour for this cake. Coconut flour works just as well but it adds a slight coconut flavor to the cake, which I don’t like as much.
If you choose to use coconut flour, use 1 tablespoon of coconut flour, instead of 3 tablespoons of almond flour.
I use Erythritol as a sugar substitute. You can use Swerve, Lakanto Monkfruit, or Xylitol, but you’ll want to cut the amount slightly to make up for the increased sweetness of those substitutes.
Then mix in the melted (but not hot) butter, egg, and vanilla. Stir it all up. It should be the consistency of regular cake batter. Not too dry, not too runny.
Carefully stir in the blueberries. Then pour the batter into your prepared mug.
Put the mug in the microwave for 60 seconds. I use an 800-watt microwave and 60 seconds is perfect.
I’ve never had one come out not fully cooked, but if yours doesn’t seem springy and fully cooked, or if it still has a wet top (you can still see raw batter), put it back in for another 10 seconds. A lower wattage microwave might cook the cake slower.
Alternately, a higher wattage microwave could over cook the mug cake, so if this cake overcooks in 60 seconds, you’ll need to cut the time down or cook at a lower power next time.
While it’s cooking, mix up the frosting. It’s just melted butter, heavy cream and powdered sweetener (like Erythritol or Swerve). Mix it up until smooth.
When the cake is done, you can add the frosting eat it directly from the mug, or turn it out onto a plate and drizzle with the frosting.
Have extra blueberries left over? Try these Keto Blueberry Muffins.
Keto Mug Cake FAQs
If you’ve never made mug cake before, you might have a few questions. Here are some of the most frequently asked questions I receive about this recipe.
Mug cakes are so easy to make that it gets you wondering how it works, especially since it takes so long to bake a cake in the oven. The magic of a mug cake is in the leavening agents, which are the egg and baking powder.
When heated, the baking powder reacts with the other ingredeints and forms bubbles that help the cake rise, while the rest of the ingredients cook.
You’ll need the ingredients (obviously), but then the only other things you need are a microwave and a microwave-safe mug. I just use my regular tea/coffee mugs. You could also use a ramekin. You just need a mug or ramekin that’s larger than the cake ingredients, because it does rise a couple of inches in the mug.
I cook my mug cake at full power in a 900-watt microwave. If you have a more powerful microwave, you may need to cook the cake for 70 or 80 seconds instead of 90. Once you’ve cooked one mug cake, you’ll know for next time.
In my opinion, it’s better to under cook then over cook, so if this is your first mug cake cook it for 80 seconds on full power. If it’s still wet in the middle, cook for 10 seconds longer. If it’s a bit tough or dry, you can reduce by 10 seconds next time you make it.
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Keto Blueberry Mug Cake
For the frosting
- 1 tsp butter melted
- 2 tsp heavy cream
- 2 tsp powdered erythritol
- Spray or rub the inside of a microwave-safe mug with cooking oil or butter.
- Mix the almond flour, baking powder, and erythritol in a small bowl. Stir in the butter, egg and vanilla extract until smooth. Add the blueberries and stir gently to incorporate.
- Pour the batter into the mug.
- Cook in the microwave on high for 60 seconds.
- If serving with the frosting, mix the butter, cream and powdered erythritol until smooth. If too thick to drizzle, add extra cream. Drizzle over the mug cake. Serve.
Other types of sugar substitute can be used, like Swerve or Xylitol. Remember that erythritol is 70% less sweet than those.
Some microwaves are more or less powerful. I cook mine for 60 seconds on full power in an 800watt microwave. You may need to adjust the cooking type based on the wattage of your microwave. The top should be spongy and not wet.
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice.