Keto Lemon Mug Cake (Ready in 1 min!)

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This Keto Lemon Mug Cake is a delicious keto dessert or breakfast that you can make in just 1 minute in the microwave.

» Check out these other great keto mug cakes! We especially love this Cinnamon Roll Mug Cake and this Low-Carb Carrot Mug Cake.

Lemon Mug Cake

When you’re craving something sweet and familiar, like a lemon poppy seed 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 lemon 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.

Lemon Mug Cake

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 lemon 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 Lemon 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.

Lemon Mug Cake Batter

I personally prefer to use coconut flour for this cake. Almond flour works just as well but I like the slight coconut flavor that gets added to the cake when you use coconut flour.

If you choose to use almond flour, use 3 tablespoons.

Lemon Mug Cake

Mix the dry ingredients together in a bowl – that’s the coconut flour, baking powder, and sugar substitute.

I use allulose as a sugar substitute. You can use Swerve, monkfruit, erythritol or xylitol. It’s really up to you which sweetener you use. The reason I use allulose is because it doesn’t have the cooling effect you get with erythritol. You can buy it through Wholesome Yum. I think you’ll really like it, especially if you’re not into the cooling effect either.

Wholesome Yum - Clean Keto Foods
Learn more about low-carb sweeteners and conversion here.
Lemon Mug Cake

Then mix in the melted (but not hot) butter, egg, lemon juice and zest, and vanilla. Stir it all up. It should be the consistency of regular cake batter. Not too dry, not too runny.

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.

Mug cakes are a quick and easy way to make this no bake trifle with whip cream and berries.

Lemon Mug Cake

You can add a glaze or frosting to this cake, but I don’t think it’s needed. It has the perfect amount of sweetness. It’s such a light and spongy cake. It’s great for a light dessert, but I mostly eat it as a breakfast treat.

If you are looking for other sweet options try our keto pumpkin bread with walnut crumble or keto pumpkin cookies.

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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Lemon Mug Cake

Keto Lemon Mug Cake

This Keto Lemon Mug Cake is a delicious keto dessert or breakfast that you can make in just 1 minute in the microwave.
4.58 from 40 votes
Print Rate
Course: Breakfast, Dessert, Snack
Cuisine: American
Keyword: Lemon
Prep Time: 5 mins
Cook Time: 1 min
Total Time: 6 mins
Servings: 1 Mug Cake
Calories: 201kcal
Author: Laura


  • 1 tbsp coconut flour
  • 1/2 tsp baking powder
  • 1 1/2 tbsp erythritol or other sugar substitute
  • 1 tbsp butter melted but not hot
  • 1 egg
  • 1 tsp lemon juice
  • 1/2 tsp lemon zest reserve some for the top
  • 1/4 tsp vanilla extract


  • Spray or rub the inside of a microwave-safe mug with cooking oil or butter.
  • Mix the coconut flour, baking powder, and sugar substitute in a small bowl. Stir in the butter, egg and vanilla extract and lemon juice and half the zest.
  • Pour the batter into the mug.
  • Cook in the microwave on high for 60 seconds (may require longer depending on your microwave).
  • Garnish with the remaining lemon zest.


  • If you wish to use almond flour instead of coconut, use 3 tbsp.
  • 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.


Calories: 201kcal | Carbohydrates: 6g | Protein: 7g | Fat: 17g | Saturated Fat: 10g | Cholesterol: 194mg | Sodium: 423mg | Potassium: 61mg | Fiber: 2g | Sugar: 1g | Vitamin A: 592IU | Vitamin C: 4mg | Calcium: 160mg | Iron: 1mg

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.

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Lemon Mug Cake
Keto Lemon Mug Cake (Ready in 1 min!)

15 thoughts on “Keto Lemon Mug Cake (Ready in 1 min!)

  1. Linda says:

    5 stars
    I’m a fan of a mug cake and this recipe is a keeper! It’s keto-friendly and easy to make – who doesn’t love it?

  2. Natalie says:

    5 stars
    I’ll just swap butter for coconut oil and give this a try this afternoon. Lovely dessert. Thanks!

    • Laura says:

      I’ve tried swapping those in other recipes, but not this one. Do let us know if it doesn’t work as well with the coconut oil.

  3. Cindy says:

    I dressed this up with an icing drizzle made from vanilla protein powder, swerve, water, lemon juice and zest. Garnished with fresh berries. Delicious!

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