These easy Keto lemon bars are a real crowd pleaser. They're super moist and just on the right side of zingy. If you're in need of a fail-safe sugar free and low carb dessert recipe, you've got to try this one. It's a keeper!
In my totally biased experience, there are two cake types that literally EVERYBODY likes. One is chocolate cake and the other one is lemon cake.
It's chocolate when you're after something rich, sumptuous and indulgent, such as this Keto chocolate cake. And it's lemon when you're looking for a refreshing yet subtly sweet experience, to cleanse your palate in a most agreeable way.
I'm a big fan of lemon in desserts and have posted an amazing low carb lemon cheesecake, Keto lemon cookies and this really popular sugar free lemon mug cake on the blog already.
In terms of taste, Keto lemon bars sit somewhere in the middle between the two. It uses almond flour just like the sugar free lemon cake recipe. But due to the addition of sour cream it's even more moist - I find there's a hint of baked cheesecake texture.
Trust me, it's a truly delicious dessert experience.
I've used ground almonds for this cake, which is equivalent to coarse/grainy almond flour or almond meal, which helps with creating that super juicy sponge cake we're after.
If you want to make this cake with super fine almond flour, you'd probably have to reduce the amount of almond flour by about ¼ cup to get the same result.
How to make easy Keto lemon bars - step by step:
1.) Beat the eggs until frothy. Then add the softened butter and the sour cream (could be replaced with cream cheese) and blend in a food processor or with an electric mixer until combined.
2.) Add the lemon juice, lemon zest and powdered sweetener. Definitely, definitely do not miss out the lemon zest. It lends amazing flavour. Make sure you buy unwaxed lemons so you're not grating any chemicals into your cake!
I chose powdered erythritol for this recipe, but a brown sugar substitute would also work well here.
3.) Last, add the ground almonds / coarse almond flour and the baking powder. Mix until smooth and let the batter sit for a couple of minutes so it thickens. The batter should be thick but pourable.
4.) Line a small casserole dish with parchment paper. I used a 9 x6 inch dish, but it could even be slightly bigger - my cake bar slices were a generous 4 cm / 1.5 inch tall. Fill in the batter and bake on the middle oven shelf for 35-40 minutes.
If you prefer, you can bake this cake in a loaf tin. I have a silicone pan like this, which is also great for bread.
5.) And voila, here's the finished cake. Doesn't this colour lighten your mood immediately?!!
Topping ideas and recipe variations
If you wanted, you could enjoy your lemon bars "naked" and be perfectly happy. The topping is entirely optional, but I agree that it does add to the wow factor.
I decided to keep it quick and simple and dusted powdered erythritol over the cake.
Here are more topping ideas:
Sugar free lemon drizzle:
Mix 4 tablespoon lemon juice with 4 tablespoon powdered sweetener and drizzle over the cake.
Low carb lemon glaze:
Stir together 4 tablespoon melted butter, 4 tablespoon double cream, 4 tablespoon powdered sweetener and the juice of 1 lemon. Wait until the mixture starts to cool and thicken, then pour over the cake.
Simple Keto lemon cream cheese frosting:
Mix ½ cup cream cheese, 4 tablespoon powdered sweetener, squeeze of lemon juice and grated lemon zest. Spread over the lemon bars and grate some extra lemon zest on top.
Pull-out-all-the-stops Keto lemon curd frosting:
Make a batch of sugar free lemon curd and cool in the fridge. Whip 1 cup / 240ml of double cream until stiff and fold in the cold lemon curd. Spread over cake and grate more lemon zest on top.
I know some of you cannot have almond flour. You can try making this recipe using 1 cup of coconut flour in place of the almond flour. Coconut flour absorbs more liquid than almond flour, that's why you'll need only half the amount.
I have not tried making this particular cake with coconut flour myself, but it's the substitution amount I'd go for. If you substitute, you MAY also ned to add 1 additional egg (coconut flour goods tend to be more delicate). If you have xanthan gum, add ½ tsp. Xanthan gives a better crumb structure, but it's not essential here.
See my other lemon dessert recipes:
Tried this recipe? Give it a star rating below!
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Keto Lemon Barsfrom Sugar Free Londoner
Note: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary. ***As an Amazon Associate I earn from qualifying purchases.
- 4 eggs large
- ½ cup / 120g sour cream
- ½ cup / 120g butter, softened
- ¼ cup / 4 tbsp lemon juice
- zest of 1 lemon
- 2 cup / 200g almond flour or ground almonds / NOT super-fine almond flour!!!!
- 2 teaspoon baking powder
- ⅓ cup / 40g powdered erythritol
- Preheat the oven to 175 Celsius / 350 Fahrenheit.
- Beat the eggs until frothy. Add the sour cream and softened butter and blend with a food processor or electric mixer until combined.
- Add ¼ cup (4 tbsp) of lemon juice, the grated zest of 1 lemon and ⅓ cup powdered erythritol. Blend.
- Lastly, add the almond flour and baking powder and mix until you have a smooth batter.
- Line a 9x6 inch casserole dish / baking pan with parchment paper and fill in the dough.
- Bake in the middles shelf of the oven for 35-40 minutes until the top is lightly browned and a skewer inserted comes out clean.
- Leave to cool completely before cutting or removing from the pan. Almond flour cakes are fragile when hot, but they firm up as they cool down.
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Just made these and they are so delicious.. drizzled with lemon juice and powdered erythritol.. couldn't stop eating them ... thanks for your lovely recipes....
Could you give me the weight in grams of a large egg you use for your recipe?? I have chickens of my own and they produce medium and large eggs.
Hi Suzy, a large egg in its shell should weight 63g-74g.
Delicious! Another brilliant recipe, thank you.
Hi, Katrin - I only have "finely sifted" almond flour; by how much should I reduce it?
Note: I submitted this question recently for another of your recipes but I can't remember which one.
Hi Addie, the rule of thumb is to use about 10% less super-fine almond flour over ground almonds. However, almond flour brands all differ wildly. And when a brand is "finely sifted" it does not necessarily mean it's super-fine. Try using a little less and see if that gives you the same result as the batter shown in the images and in the video.
I'm using the Blue Diamond brand from Walmart here in Florida. I think I read in one of your recipes a while back to use two tablespoons less of the super-fine flour so I'll try that.
Just perfect, so easy and so delicious. Making it again shortly ...
I don't use butter at all because of high cholesterol.
Could I substitute EVO in the lemon cake recipe ?
I think that would work. I used olive oil instead of butter in this Keto Almond Flour Olive Oil Cake and it worked beautifully.
I would give this 10 stars if I could! I chose to make this because the bars were so freaking gorgeous in your photo! Readers mentioned muffins and adding fruit, so I added dried cranberries and ended up with 14 beautiful lemony and SUPER MOIST muffins. I added the simple glaze because you can never have enough lemon. 🙂 Definitely one of the best things I have ever baked (including my old wheat flour days). Thank you Katrin for your amazingly foolproof recipes! I know it takes tons of hard work to come up with each recipe, and you never let us down!
Aah, thank you so much! I'm so happy you liked the recipe.
Easy and taste great, nice texture
Delicious. I used a 9.5" spring form pan and it worked fine. I followed the recipe exactly.
Can eggs be replaced with flax seeds soaked in water? Also can almond flour be substituted with coconut flour. If this is the case, what would be the equivalent be?
Love your recipes!
Hi Sylvia, I don't recommend using flax eggs instead of the eggs. The eggs help with the rise and fluffiness of the cake. In terms of the flours, you can replace almond flour with 1/3 the amount of coconut flour. You need less coconut flour because it absorbs more moisture. Coconut flour recipes often use an additional egg as well because it is more brittle than almond flour.
This was the loveliest lemon cake. So fluffy and makes generous portions. It was still lovely frozen and defrosted. I am so grateful you shared this with us. Thank you.
So happy you enjoyed the recipe!
What if I only have super fine almond flour? How much would I need?
I would use 2 tbsp less.
Can I use coconut milk or coconut cream instead of sour cream?
Yes, I think that could work! Make it a similar consistency to sour cream.
It worked with coconut cream and I also tried with coconut yoghurt and was delicious
Also in the video of the cakes being made, the machine you used isnt the same as mine, what attachments would be best a whisk or k attachment for my mixer? I'm making it for first meeting of my partner's parents and want it to be right.
I'm not sure what a k attachment looks like - but my best guess is that both will work. It's not a tricky batter!
I cannot find powdered erythritol in any supermarkets can standard Erythritol get the same result?
You can always blend your granulated erythritol in a food processor and powder it that way. But granulated sweetener will work as well.
Didn't realise softened butter probably meant melted butter 🙁 my butter is not fridge cold as sits out on the kitchen counter in a butter dish so thought that would be ok but my batter is sooooo lumpy 🙁 I've chucked it in the oven anyway so hopefully it turns out alright! Will report back! Fingers crossed...
Mixing batter long enough normally sorts out lumpiness. However, it's best if your ingredients are of a similar temperature to start with. If you use very cold eggs, for example, this could cause your butter to cool and become lumpier. How did your cake turn out in the end?
I made this one for Christmas and loved it. I am wondering does it freeze well?
Thank you for a wonderful webpage!
Glad you like the recipe! Yes, this cake freezes well. All almond flour cakes do.
Fantastic recipe, thank you! It came out delicious and I’ll be making it again 😀
Is this salted or unsalted butter
Hi Jo, I always use unsalted butter.
I really live these lemon bars, they are soft and lemony. I made cream cheese frosting with lemon juice on the top. If it very tasty. Thank you for the recipe, will definitely make it again.
Just made this recipe into 9 cupcakes, absolutely delicious has to eat one whilst still warm so light, fluffy and most, not sweet so may add a lemon/sugar/butter glaze to finish the top because I only have Xylitol . Didn’t have any sour cream so used cream fraiche and think I’ll double the amount of lemon zest next time. Gr8 recipe, thank you.
Can I use monk fruit sweetener instead of erythritol?
I've never used pure monk fruit sweetener, so I'm not sure about the measurements. If you mean an erythritol monk fruit mix such as by Lakanto, you can replace it 1:1
Thank you for another great recipe, Katrin! All your cakes and breads have a great texture! The second time around, I did add a bit more sweetener and 1 tsp lemon extract. Love all the various toppings you suggest! It's always nice to have options! I like that your servings are generous, without too many calories and carbs.
Glad you liked it Joyce!
Hi, I'm having trouble with the macros calculation.... how many Net carbs are there in one serving?? I'm uploading the recipe in MyFitnessPal and I can't reach that number... It says here 3.6g carbs and 1.9g fiber, so that would make 1.7g net carbs... Is that correct or am I mistaken?? Thank you!!
Yes, that's what my nutrition calculator came up with!