Big flavor, light texture: Try this easy, moist keto lemon mug cake with a deliciously zingy lemon glaze. It contains only 6 ingredients and cooks in 90 seconds.

This flavorful keto mug cake is a new favourite of mine and I have made it several times already.
It is an almond flour sponge cake with a moist yet light and airy crumb texture and it is packed with zingy lemon flavor. I have topped it with a creamy lemon glaze.
Think of this cake as a super-speedy cheat's version of this Keto Lemon Pound Cake.
Jump to:
🌟 Why You'll Love This Recipe
- This cake is ready from scratch in 3 minutes. It is brilliant as a spontaneous treat or as a last-minute dessert.
- It is naturally gluten-free and keto friendly with only 2.7g net carbs per portion.
- I shared the cake in the recipe video with a diabetic neighbour who popped by. She thought it was "divine". But, my carb-loving children also enjoyed the taste. This is a sugar free dessert that does not taste sugar free!
Ingredients
You only need 6 ingredients!
- Almond flour - I've made this cake with both super-fine almond flour and with ground almonds. When using almond meal or ground almonds, add 1-2 additional tablespoons.
- Heavy cream - also called double cream. We are using this instead of butter.
- Powdered sweetener - I used powdered erythritol. You can also use monk fruit sweetener or erythritol blends such as Swerve. Xylitol and allulose work as well.
- Egg - large
- Lemon juice - Fresh lemon juice tastes best. However, bottled lemon juice will also work.
- Baking powder
Instructions
This section contains step-by-step instructions and photos that show how to make this recipe. See the recipe card for full information on ingredients and quantities

Step 1: Mix the dry ingredients - almond flour, powdered sweetener and baking powder in a small bowl.

Step 2: Add the wet ingredients - lemon juice, cream and an egg. Mix with a fork until combined.

Step 3: If you want to turn the cake out onto a plate later, transfer the cake batter into a well-greased bowl or ramekin. Or, separate the mix into 2 mugs.

If you want to eat it straight from the bowl, microwave in the bowl you mixed the batter in.

Step 4: Microwave on high for 90 seconds.

Step 5: Turn the keto lemon mug cake out onto a plate and top with lemon drizzle glaze.
Or, enjoy it straight from the bowl!
Top Tip
I've had my fair share of microwave mug cake accidents! If your mug, ramekin or dessert bowl is too small, the batter will overflow as it rises and make a mighty mess.
It's important that your vessel has a volume of at least 200 millilitres and is wider rather than narrow and tall. Mugs or ramekins should not be filled with batter more than half. Always have a few fingers of free space between the batter and the rim.
Recipe FAQs
Use coconut cream or coconut oil instead of the cream.
No, you would have to change other parts of the recipe too. Make my coconut flour mug cake and add lemon.
It's not necessary for the recipe. However, I think it makes the cake taste even better.

Variations
Here are ideas how you can change up the recipe:
- Poke little holes into the finished cake. When you pour over the glaze it sinks into the holes and makes the cake even more moist.
- Add 1 teaspoon of poppy seeds.
- Grate lemon zest into the batter.
- Add a few blueberries or raspberries into the batter.
- Use lime instead of lemon
- Blend the egg with an electric mixer until double in size and pale in colour. This will make for an even lighter sponge.
- Add a cream cheese frosting (2 tablespoon cream cheese, 1 teaspoon sweetener and a little lemon juice)
- Top with sugar free whipped cream
Microwave Timings
My microwave operates at 900 watts and my cake took 90 seconds to cook. Here's a quick overview of recommended baking times for this sugar free lemon mug cake recipe:
- 600W = low power. 110+ seconds.
- 800W = 100 seconds.
- 900W = 90 seconds.
- 1000W = 80 seconds
- 1200W = 60-70 seconds.
After these times, check whether the cake is done. If it's still undercooked, add increments of 10 seconds.
Oven Instructions
To make this cake in the oven, bake for around 12-15 minutes at 180 Celsius (160C fan) or 350 F (320F fan assisted). Test with a toothpick of knife to make sure it's fully cooked.
Baking in 2 ramekins means less oven time, using one larger ramekin will increase the baking duration.
Storage
Refrigerator: Store leftovers in the fridge for up to 4 days.
Freezer: All almond flour cakes are suitable for freezing. Freeze for up to 3 months.
Related Recipes
I adore mug cakes. My first attempt at making a cake in the microwave was this divine low carb Christmas pudding.
Since we don't eat Christmas food all year round, I expanded my repertoire quickly. Try this keto chocolate mug cake, my vanilla keto mug cake or this divine keto peanut butter mug cake. Here are more keto mug cakes to try:
- Keto Blueberry Mug Cake4 Minutes
- Keto Lava Mug Cake4 Minutes
- Coconut Flour Mug Cake4 Minutes
- Keto Mug Cheesecake (Microwave Recipe)8 Minutes
Tried this recipe? Give it a star rating below!
★ STAY IN TOUCH on FACEBOOK, PINTEREST and INSTAGRAM for more great food and join my NEWSLETTER for the latest updates and a FREE EBOOK.★
Recipe

Keto Lemon Mug Cake
Video
Ingredients
For the cake
- 4 tablespoon almond flour extra fine, or 5-6 tablespoons ground almonds
- 2 tablespoon heavy cream
- 1 ½ tablespoon powdered sweetener
- 1 egg
- 2 tablespoon lemon juice
- ½ teaspoon baking powder
For the glaze
- 1 tablespoon unsalted butter
- 1 tablespoon heavy cream
- squeeze of lemon juice
- 1 tablespoon powdered sweetener
Instructions
Cake
- Grease 2 ramekins, mugs or 1 microwave-safe bowl with melted butter. I used a glass dessert bowl.
- Mix all dry ingredients - almond flour, sweetener and baking powder - in a separate bowl.
- Add all wet ingredients and mix thoroughly with a fork. If you find your dough is too liquid add more almond flour.
- Transfer batter into your bowl or mugs and level the top.
- Microwave on high for 90 seconds.
- Turn upside down onto a plate once cooled or enjoy straight from the bowl.
Glaze
- Melt the butter, then stir in the cream, lemon juice and sweetener.
- Let cool until the glaze begins to thicken. Spoon or pour over cake.
Notes
- 600W = low power. 110+ seconds.
- 800W = 100 seconds.
- 900W = 90 seconds.
- 1000W = 80 seconds
- 1200W = 60-70 seconds.











jeannie
Hi Katrin, just made this before going to bed LOL it’s very yummy . Did you post macros anywhere?.
Katrin
Yes, the nutrition info is in the recipe card 🙂
Linda
Just made and ate, wonderful taste and texture. Used bottled lemon juice and confectioner sugar to sweeten. Great recipe to play with and no huge processed leftovers to gorge on.
Ranjit
Hi!I've tried your recipe and it's great!do you think I could add cream cheese here or sub the hc?will it ruin the cake?thanks a lot!love your recipes
Katrin
Yes, I think cream cheese could work in place of the heavy cream - I haven't tried it, but they have a similar consistency.
Louise Allison
Not usually a mug cake fan - they leave me a bit ‘meh’ - but fancied something lemony! Just made this, & as I fancied a big lemon hit, I doubled the lemon in the cake & sauce (will add zest next time, but my lemons were a bit aged!!) ..... so then I needed to add more almond flour to get it less runny...... cooked for about 3.5 mins in micro (coz it was maahhooosive!!) Turned it out into a bowl, stabbed it, & drizzled the sauce over...... lush!! It will make 12 servings for me, as it’s super filling..... but just served it with sour cream and a handful of blueberries & can honestly say it’s one of the tastiest sweet things I’ve eaten on keto.... So thank you very much!
Katrin
Thanks for sharing your microwave timings for doubling the recipe!! And I love it that you loved it!!
Naomi
This is delicious, Thank you! Mine was wet also, I nearly used less liquid but made it per recipe, except I added shredded lemon zest and used 1 TBSP of swerve. very tangy, delicious, just about perfect, even very moist.
Katrin
Great news! Glad it worked out 🙂
Kris
I made this cake today. The lemon flavor is great! But mine was quite wet when it was still a batter. Since I had followed the directions completely I went ahead and cook it and it was of course quite soft. The cake itself turned out quite flat not nearly as beautiful as your picture. Like I said the flavor was good.
Katrin
If your batter did not have the same consistency as mine (shown in the video), you should add more almond flour next time.
Annette
Awesome recipe!! The best Keto friendly mug cake I’ve made (and I’ve tried a few). I’ll try the lemon zest and poppy seeds next time! When I made mine, I sprinkled a little unsweetened medium coconut over top. It created a wonderful texture and just added a little extra to the look!
Thanks for creating this recipe!!
Annette
Victoria BC, Canada
Audrey RIETHMULLER
Je viens de teste et j'adore. Merci pour cette recette
Lorie Marshall
I have made this last month December 2018, and it’s divine!! So easily in large mug,then slice in 1/2 once its sits for like 30 seconds cool down. Love it!!
Theresa C
Made this and did very little tweaking - it came out wonderfully! I did 70 seconds in a 1000 watt microwave to make sure it did not overcook. LEMON YUM! An bit of extract and 1 teaspoon of chia seeds 🙂
Bree
Hi I have made this cake 4 times now and each time it either falls apart when I turn cup upside down or the top sticks to th3 bottom of the cup...what am I doing wrong. The cake tastes delicious but is really a mess
Katrin
I use a lot of melted butter to grease the bowl I use. It may be that you need to use some more butter. Or maybe it has to do with the shape of the cup/ramekin you use. My bowl is fairly flat. It may be harder to release the cake if you used a regular cup, for example (less diameter. The third thing that comes to mind is that you may try to release the cake while it's still warm? It firms up as it cools down and would be less crumbly. Also, a container with a very smooth surface, such as glass. I hope this helps 🙂