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 1/4 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 tbsp lemon juice with 4 tbsp powdered sweetener and drizzle over the cake.
Low carb lemon glaze:
Stir together 4 tbsp melted butter, 4 tbsp double cream, 4 tbsp 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 1/2 cup cream cheese, 4 tbsp 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 1/2 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 Bars
Easy-peasy, gently sweet and super refreshing! These moist Keto lemon bars will blow you away. Check out the post for lots of topping ideas and variations, from sugar free lemon drizzle to low carb lemon curd frosting.
Ingredients
- 4 eggs large
- 1/2 cup / 120g sour cream
- 1/2 cup / 120g butter, softened
- 1/4 cup / 4 tbsp lemon juice
- zest of 1 lemon
- 2 cup / 200g almond flour or ground almonds / NOT super-fine almond flour!!!!
- 2 tsp baking powder
- 1/3 cup / 40g powdered erythritol
Instructions
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 1/4 cup (4 tbsp) of lemon juice, the grated zest of 1 lemon and 1/3 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.
Recipe Video
Recipe Notes
This lemon cake recipe works best with coarse /grainy almond flour (ground almonds in the UK).
The cake is only gently sweet. Please taste and increase sweetener to your liking if necessary.
For me, 1 1/2 lemons yielded 1/4 cup lemon juice. For extra zing, you could increase the amount of lemon juice by up to 2 additional tbsp.
Wait until the cake is COMPLETELY cooled before dusting with powdered sweetener. If it's still warm, the erythritol melts into an unsightly sludge.
Please see the post for topping ideas, from sugar free lemon drizzle to lemon frosting.
This post contains affiliate links. If you click on one of these links, I may earn a small commission – at no extra cost to you – which helps me with the running costs of the site. Thank you for supporting Sugar Free Londoner.
Maxine says
Thank you. I put sugar free jam with it. Just a touch which added to it. you are very clever. X
Katrin says
Nice idea to add some sugar free jam to the cake!
Claire says
Katrin ,
You are such an angel, sharing these yummy alternative recipes with us. I made this today in a loaf pan with collaborative coconut yoghurt (instead of sour cream ) and I used stevia as sweetener. It turned out brilliantly and the texture is so beautiful.
Thank you for a new favourite.
Claire xo
Katrin says
So good to hear it works with coconut yoghurt!
Vanesa says
Hi there, I just made this cake, followed every detail and ingredient and cooked it for 40 minutes . I waited for it to cool down before cutting it. I just did and it is very wet. I wonder if it is the greaseproof paper I used to line the pan. I am wondering whether to put it in the oven again removing the paper. Any ideas why this happened?
Katrin says
I’m wondering if it is because the cake is undercooked or whether it’s simply a little bit of butter? Is it still doughy the middle? Then it would need some more time in the oven. Otherwise it should be fine!
Vanesa says
Hi again I put in the oven again and just took it out it is still wet all over, even inside. I am so sad. It isn’t undercooked. I will not wrong it. I may toast it and see but it looks oily. Maybe it was the butter I used (Kerrygold) or the almond flour, maybe I need to put more??? I would take a pic and send it to you if I could.
Katrin says
Hi there, You can always email me a pic at Katrin@sugarfreelondoner.com. So, let’s figure out where the issue was. Kerrygold butter is absolutely fine, that’s definitely not the problem. It must have something to do with the consistency of your dough, so maybe your measurements were off. How do you measure your ingredients?
Joan Shields says
We just loved this lemon cake! I made it as directed the first time but with fine grind almond flour and part Splenda and eryithritol/ monk fruit blend. I iced it with cream cheese frosting to which I added lemon juice and Splenda for sweetener. The flavour and texture were just like a scratch cake I used to make before keto.
I made it again today and stirred a few frozen blueberries into the batter and backed a couple of minutes longer. I’m sure this will be even better.
Thank you for a great recipe!
Katrin says
Blueberries in this cake would be delicious!!!
Maria says
Other than the dust of powder sugar substitute, does this cake has any other sweetener??
Katrin says
No, it’s just the powdered erythritol. It’s a 1:1 substitute for icing sugar. If you have granulated erythritol/xylitol, you can blitz it and make your own powdered version. I hope this helps 🙂
Klaudia says
Could you add lime as well?
Katrin says
Yes, absolutely!
Sophia says
Thank you so much for your delicious healthy recipes, appreciate it so much I made the lemon bars the moisture was excellent , but mine was dark in color , I realized because the almond meal I used was not blanched , but it was delicious thanks again , please keep the recipes coming , Enjoying them all, Many Thanks
Katrin says
Glad you liked them!!!
Ami says
The cream cheese stuck to the paddle and didn’t mix in at all. Had to throw it out… Anyone else experienced this?
Katrin says
Hi Ami, if you’re using an electric mixer, you should have no problem mixing it. What a shame you ended up throwing it all out! I really hope you’ll try again.
Maha says
Beautiful cake. My luck is usually bad with keto almond cakes but this cake came out perfect. I’m in love with it. its moist and delicious. Thank you so much for the recipe!
Katrin says
So glad you like it!! Thank you for your comment 🙂
Denise says
Hi Danielle,
Always love your recipes. I’m trying this today and ground the almonds finely as you suggested; but it sure doesn’t look nice and yellow like yours? Wondering why that might be? I’m covering with your lemon curd frosting, so that should help with the color issue.
Katrin says
Hi Denise, maybe you’re using almonds with the skins on? This would make the cake darker, but it would still taste just as good. in fact, it would be healthier – more fibre! I buy my almonds ground – in the US they call it almond flour, here in the UK it’s called ground almonds. All the same thing.
sally says
I want to make your lemon bars, but I only have granulated erythritol and granulated monk fruit. Will either of these work? It looks delicious.
Katrin says
Yes, as it’s a cake you can use regular granulated erythritol if you wish.
Violeta says
I love your page! Thank you
Katrin says
Glad you like it!!!! 🙂
SelinaUK says
When I enter the ingredients and quantities into Carb Manager and Keto Diet apps it’s calculating net carbs to be 5 net carbs per slice. Why?
Katrin says
Ingredient values will always vary slightly depending on the brands you use.
Cecilia says
Hi there!
I love your page! The recipes are not only looks delicious but also tastes as good as it looks.
Just wondering if I can substitute full fat (11%) yogurt with the sour cream. I don’t have sour cream right now and want to make it tonight.
Thanks so much for all your wonderful recipes!
Cecilia
Katrin says
Hi Cecilia, yes, that would work!
Nicole says
How can I make this dairy free?
Katrin says
I’d replace the butter with coconut oil and the sour cream with coconut yoghurt. I”m not sure where you’re based, but here in the UK COYO or Coconut Collaborative are good brands for coconut yoghurt.
Kate Koger says
Got this in the oven right now! So can’t wait to have it tonight! Again a wonderful recipe that is easy to put together, easily accessible ingredients and lemony! What’s not to love??!!!!
Katrin says
Hope you liked it Kate!!!
Amy says
Hi there! =)
What can i use instead of sour cream? As im lactose intolerant
Katrin says
Hi Amy, I would use coconut cream or a good quality coconut yoghurt.
Danielle says
I only have the super fine almond flour. Will it work with this recipe? Thanks!
Katrin says
Hi Danielle, you may need to use a bit less almond flour if yours is super fine. Try 1/3 cup or 1/4 cup less and see if the texture is good.
Carol Bedford says
Made this yesterday put into a loaf tin once cooled covered in lemon drizzle truly gorgeous thank you soo much for all your amazing recipes
Katrin says
Yum!!! Glad it was a success!
Kate says
What an amazing recipe! Made it last night, trying not to eat the whole thing in record time!
Katrin says
Haha, that’s the only problem with it!
Kim Seaton says
OMG….Just Devine…finally a recipe that lives up to the imagination…thank you ❤️
Nicole says
If we can’t get coconut flour, can I use almond flour.
Katrin says
Hi Nicole, the recipe actually uses almond flour. If you want to use coconut flour instead, simply halve the amount stated for almond flour.
Kristy says
This is delicious! Have never had lemon cake before but I love this! Just the right amount of lemony flavour and sweetness… My husband has to use his will power to stop at one. This will be a permanent fixture in our house, just like your cinnamon scrolls! Yum!
Katrin says
Wonderful!!!!!
Diana moreno says
Simplemente Deliciosa
Charla says
Hi! Made this last night with coconut flour, the extra egg you suggested as well as xanthan gum. Turned out great, thanks! It’s the perfect snack for when you’re travelling (no toppings then).
Katrin says
Wonderful! So glad you like it 🙂
Danielle says
Hi! Love your page! I am unable to use almond flour due to a nut hypersensitivity. Can you please advise how much coconut flour you would use instead? I would LOVE to try this, it looks incredible! Thank you so much xx
Katrin says
Hi Danielle, 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 1/2 tsp. Xanthan gives a better crumb structure, but it’s not essential here.
JK Collins says
What’s a “serving”???? The nutrition facts are “per serving “ but NOWHERE does it state what a serving is!!!!!!
Katrin says
Hi there, I’m sorry this was not clear – I always state the amount of servings in the recipe card. I cut my cake into 8 generously-sliced bars. One bar is 1 serving.