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 almond flour mug cake, my friends, is a revelation. It is such a treat. To think that you can make a delicious keto dessert that's ready in 3 minutes!
It's like the super-speedy cheat's version of this Keto Lemon Pound Cake.
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 keto vanilla mug cake or this divine keto peanut butter mug cake.
This sugar free lemon mug cake is definitely a new favourite, and I have made it several times already.
The cake you can see in the recipe video I shared with a diabetic neighbour who popped by. She thought it was "divine".
🌟 Why You'll Love This Recipe
- Moist sponge with a light and airy crumb texture
- Packed with zingy lemon flavor
- Topped with a creamy lemon glaze
- Keto friendly - only 2.7g net carbs per serve
- Gluten-free
- Easy and quick recipe - cooks in 90 seconds
Ingredients
You only need 6 ingredients to make this easy treat:
- 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 your lemon cake out onto a plate and top with lemon drizzle glaze.
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.

FAQ
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.
Baker's notes
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 keto 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.
More keto lemon recipes
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Recipe

Keto Lemon Mug Cake
from Sugar Free LondonerNote: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary.
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.
Video
Notes
- 600W = low power. 110+ seconds.Â
- 800W = 100 seconds.
- 900W = 90 seconds.Â
- 1000W = 80 seconds
- 1200W = 60-70 seconds.Â
Nutrition
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Jules
I made this with sour cream instead of heavy cream and it was delicious!
Hannah
I like this enough that I decided to make a mix with it. I measured out all the dry ingredients for one recipe (two small mug cake) and it came out to be 42 g. Then I just mixed together eight times the amount of each dry ingredient and I'm storing it in a container. I microwave them in silicone cups and they pop out perfectly with no sticking.
Hannah
Actually I ended up making a mix large enough for 12 batches. Assuming my calculations were correct, this is how I mixed it! Three cups almond flour plus 1 cup and 2 tbsp powdered sweetener and two tablespoons baking powder. I think I'm going to make some of your other mug cakes into pre-made mixes as well. I stuck a label with the rest of the recipe, wet ingredients plus microwaving time, on the outside of the container of the dry mix. So it should be super fast and convenient to make them.
Sybille Seidel
I love any desserts with Lemon Was wondering how this recipes numbers would change if I added poppy seeds to it and would not work in a mug cake Love the chocolate ones as well
Katrin Nürnberger
I think you can add a teaspoon of poppy seeds without having to change the rest of the ingredients.