This keto Vanilla Cake in a Mug is made with coconut flour and sugar substitute, making it the perfect low-carb, sugar free alternative to regular cake.
This is the first sugar-free, keto-friendly vanilla cake that I’ve felt is just as good – maybe even better – than regular cake. It’s what we now use for birthday cakes and no one misses the sugar and flour. In fact, I think you’d be really hard pressed to even know it was different.
If you’re no longer eating sugar, but still want a piece of cake once in a while, this is the recipe to save for those occasions. It’s so moist and has a great vanilla flavor a slight hint of coconut. The frosting is light and airy.
Does It Have to Be Made in a Mug?
This cake is meant to be just 2 servings. It’s a quick and easy cake to make in the microwave when you have a craving or just want to make a quick dessert. So we make it in a mug, like these other amazing mug cakes.
You can make this cake in a ramekin or other small dish, if you’d rather it have a different shape. Or you can double the recipe and make it in a glass loaf pan, if you want a larger cake.
I use allulose as a sugar substitute. You can use Swerve, monkfruit, Erythritol or Xylitol. It’s really up to you. The reason I use allulose is because it’s a no calorie no carb sweetener like erythritol, but it doesn’t have the cooling effect. I get allulose directly through Wholesome Yum. I think you’ll really like it, especially if you also don’t like the cooling effect.
Learn more about low-carb sweeteners and conversion here.
How to Make Keto Vanilla Cake in a Mug
To make this keto vanilla mug cake, you’ll need a microwave-safe mug that’s at least 16 oz. I use my regular coffee mug and it has plenty of space for the cake to expand. You can also use a 16 oz or larger ramekin.
Rub a little olive oil or coconut oil inside the mug to prevent sticking.
I personally prefer to use coconut flour for this cake because it comes out fluffier, tastes more like a regular cake, and has a very nice texture and flavor.
Almond flour works too, but the texture and moistness just isn’t the same. If you choose to use almond flour, use 6 tablespoons rather than 2 tbsp coconut flour, as almond flour is not as absorbent as coconut flour.
Whisk the egg, almond milk, cream, and vanilla together in a bowl. Add the coconut flour, baking powder and sugar substitute. Whisk until smooth.
Pour the batter into your prepared mug. Put the mug in the microwave for 90 seconds. I use an 800-watt microwave and 90 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 90 seconds, you’ll need to cut the time down or cook at a lower power next time.
How to Make the Frosting
This is a quick frosting that comes together just as quickly as the cake. You could use any frosting recipe you want to frost this cake.
If you want a cream cheese frosting, just add cream cheese to the cream before whipping. You can also add cocoa powder for a chocolate topping.
Before you get started, it’s imperative that the cream is very cold when you start. If it’s not super cold, it can be difficult to whip, or it might not whip at all. Start with cold cream and a cold bowl.
For this frosting, beat the heavy cream, powdered sweetener and vanilla extract together in a bowl until stiff peaks form. Keep the frosting cool until you’re ready to put it on the cake. I’d suggest not making it too far in advance, because the stiff peaks could collapse after an hour or so.
Once the cake is cooled, scoop on the whipped topping. Add sugar-free sprinkles, if you want to make it more festive.
Can I Make This Cake Ahead of Time?
This cake is meant to be made right before serving. That’s the joy of a mug cake. It’s so quick and easy to whip up that you can make it on the fly. If you make this cake in advance, be sure to wrap it well in plastic wrap or in a ziplock bag, to seal in the moisture. It can become dry if it sits too long.
The same goes for the frosting, which is meant to be made right before serving. It does stay whipped for a few hours, but can begin to droop a bit or even break after a few hours.
How Many Carbs In This Cake?
This keto vanilla cake in a mug has 4 net grams of carbs per serving. There are 2 servings in this cake, unlike most mug cakes which are made for one person. Since this cake is often made as a birthday cake that you’ll likely be sharing with someone, it’s a bit larger than usual.
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Keto Vanilla Cake in a Mug
- 1 egg
- 1 tbsp almond milk or other milk substitute
- 1 tbsp heavy cream
- 1/4 tsp vanilla extract
- 2 tbsp coconut flour
- 1/2 tsp baking powder
- 2 tbsp allulose or erythritol, swerve, xylitol
For the whipped topping
- 1/4 cup cold heavy whipping cream
- 1 tbsp powdered allulose or other powdered substitute
- 1/4 tsp vanilla extract
- Sugar-free sprinkles, optional
- Lightly grease a large mug or ramekin (at least 16oz).
- Whisk the egg, almond milk, cream, and vanilla together in a bowl. Add the coconut flour, baking powder and sugar substitute. Whisk until smooth.
- Pour into the prepared mug. Microwave for 90 seconds on high. Cool completely.
- Beat the cold heavy whipping cream, powdered sweetener and vanilla extract together in a chilled bowl until stiff peaks form.
- Once the cake is cooled, scoop on the whipped topping. Add sprinkles, if desired.
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.
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.
How do mug cakes work?
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 ingredients and forms bubbles that help the cake rise, while the rest of the ingredients cook.
What do I need to make a mug cake?
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.
What wattage do I cook this on?
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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Laura is an avid home cook and recipe creator. She shares her favorite low-carb recipes here that are both easy to make and full of flavor, so you don’t even miss the carbs.