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Low-Carb Lemon Bars

4.5 stars, average of 38 ratings

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For all you lemon lovers, this is the slice for you. This delicious lemon slice features a biscuity base topped with a layer of zesty homemade lemon curd.

You can leave this slice as is, with the gorgeous lemon curd as the top, or sprinkle it with some powdered erythritol, Swerve or xylitol. While I did add the powdered low-carb sweetener for these photos, I actually prefer it without personally as I don’t like my desserts too sweet, and the lemon layer here is fairly sweet to balance out the tartness of the lemons.

Substitutions and Allergy-Friendly Options

For dairy-free lemon bars, you swap the butter for ghee (although it is dairy, it's usually well tolerated) or virgin coconut oil. For nut-free lemon bars, simply swap the almond flour for an equivalent amount of ground sunflower seeds (you could even mix in some unsweetened shredded coconut!).

Some people are sensitive to xanthan gum and experience GI issues and bloating. If you can't use xanthan gum, you can swap it for psyllium powder. We'd use 2 to 3 teaspoons of psyllium powder, 1 tablespoon of gelatine powder or 1 to 2 tablespoons of flax meal. Alternatively, skip the almond milk and xanthan gum and use one large egg instead.

Glucomannan powder is usually well tolerated. It is made from konjak root just like shirataki noodles. You could swap it for about one 2 to 3 teaspoons of arrowroot powder, just remember to recalculate your macros as there are extra carbs. For a carb-free thickening option, use 1 to 2 extra egg yolks.

Finally, some of you may find the lemon layer too tart. If you prefer your lemon slice sweeter, use juice from Meyer lemons or limes. Both of these options are sweeter than regular lemons. You can also add low-carb sweetener to taste.

Hands-on Overall

Allergy information for Low-Carb Lemon Bars

✔  Gluten free
✔  Nut free
✔  Nightshade free
✔  Avocado free
✔  Coconut free
✔  Fish free
✔  Shellfish free
✔  Beef free

Nutritional values (per serving)

Net carbs2.1 grams
Protein3.9 grams
Fat9.9 grams
Calories113 kcal
Calories from carbs 7%, protein 14%, fat 79%
Total carbs3.6 gramsFiber1.5 gramsSugars1.2 gramsSaturated fat2.2 gramsSodium15 mg(1% RDA)Magnesium35 mg(9% RDA)Potassium108 mg(5% EMR)

Ingredients (makes 16 squares)

Lemon curd layer:
  • 1/2 cup fresh squeezed lemon juice (120 ml/ 4 fl oz), or up to or more to 3/4 cup for more zing
  • grated zest of one to two lemons, to taste
  • 1/3 cup granulated Erythritol or Swerve (67 g/ 2.4 oz)
  • 2 large eggs
  • 2 egg yolks
  • 3/4 tsp glucomannan powder (or up to 1 tsp if using more lemon juice)
Optional topping:


  1. Preheat oven to 170 °C/ 340 °F (conventional), or 150 °C/ 300 °F (fan assisted). To make the crust, combine all ingredients in a bowl and mix well.
  2. Line a tray (either 20 x 20 cm/ 8 x 8" or 23 x 15 cm/ 9 x 6" tray) with baking paper, and then pour the mixture in, pressing down firmly. Bake 15 to 18 minutes, until just starting to brown. Low-Carb Lemon Bars
  3. While the crust is baking, whisk together all of the lemon curd ingredients in a bowl.
    Low-Carb Lemon Bars
  4. Pour onto the base as soon as it comes out of the oven (while its still hot). Spread across the base, and return to the oven, lowering the temperature to 160 °C/ 320 °F (conventional), or 140 °C/ 285 °F (fan assisted). Bake 15 to 18 minutes until just set in the centre.
    Note: To prevent the top from cracking, place a ramekin filled with water in the oven. The steam will help keep the top moist. Low-Carb Lemon Bars
  5. Allow the pan to cool completely, and then move to the fridge for at least 2 hours before slicing.
    Low-Carb Lemon Bars
  6. Sprinkle with powdered low-carb sweetener before serving.
    Low-Carb Lemon Bars
  7. Store in a sealed container in the fridge up to 5 days. Low-Carb Lemon Bars

Ingredient nutritional breakdown (per serving)

Net carbsProteinFatCalories
Almond flour (blanched ground almonds, almond meal)
1.1 g2.7 g6.6 g74 kcal
Butter, unsalted, grass-fed
0 g0 g2.2 g19 kcal
Almond milk natural (unsweetened)
0 g0 g0 g1 kcal
Erythritol (natural low-carb sweetener)
0.1 g0 g0 g1 kcal
Xanthan gum, thickening agent
0 g0 g0 g0 kcal
Lemon juice, fresh
0.5 g0 g0 g2 kcal
Lemon zest (peel), fresh
0 g0 g0 g0 kcal
Erythritol (natural low-carb sweetener)
0.2 g0 g0 g1 kcal
Egg, whole, fresh, raw (free-range or organic eggs)
0 g0.8 g0.6 g9 kcal
Egg yolk, fresh
0.1 g0.3 g0.6 g7 kcal
Glucomannan powder, thickening agent
0 g0 g0 g0 kcal
Total per serving
2.1 g3.9 g9.9 g113 kcal

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Dearna Bond
Creator of

Dearna Bond

Dearna is a passionate foodie and food photographer, and loves sharing her knowledge and enthusiasm for both via her food blog and online photography courses.

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Comments (14)

Delicious and very lemmony. 2 Questions.
Can i substitute xanthum gum for glucommanan powder? I used arrowroot which worked well but want to avoid unnecessary carbs.
My base was soft and I wondered if supposed to be more crispy texture?
Tx so much for water in oven tip. My topping was so smooth. ❤️

These are my favourites, I love anything lemon! I think you can use glucomannan powder. I personally don't use xanthan gum very often as it can upset my stomach. Another option would be to use 1 egg and skip the almond milk and xanthan gum. And yes the base will get softer as it will get moist from the lemon topping, plus this kind of base is generally harder to crisp up and keep it that way.
Oh and I'm sorry it took a while to reply, I have been enjoying the fourth trimester with our twins 😊

Can we use ground macadamia nuts instead of almond flour?

Yes! Ground macadamia nuts would be perfect. I'd also reduce the amount of butter to only 1 to 1.5 tbsp as macadamia nuts are more fatty.

This is fantastic! Gorgeously tart and fresh, both my husband and I loved it, and I'm not usually that keen on lemony desserts although my husband loves them. The only thing I changed was to use about 1-2 tsp of arrowroot powder instead of glucomannan as I didn't have any, and it still set perfectly. I had this with some unsweetened whipped cream on top and it was utterly decadent. Thank you so much for sharing this.

Thank you for your feedback Anu, glad you enjoyed! I usually add a bit more lemon juice & zest into mine but I do like mine quite tart 😊

Hello again! One question please -- Do these freeze well? I am planning to make another batch soon, but we may not be able to get through the whole thing in 5 days! 😊

They do indeed! I freeze most of the larger desserts I make because we can rarely eat them in time before they go bad :-D

Thank you for the recipe! I made them last night and they are great! In the curd part I added one more egg and about 1/2 tsp of agar agar (did not have arrowroot powder or glucoman). From the extra egg white I made a meringue following the Low-Carb Lemon Meringue Parfaits recipe.
Once the curd was done, I just popped the meringe on the top and put it back to the oven for a minute until they got some color. They turned about so good!

Thank you so much for your feedback and to the meringue suggestion - that's such a great idea!

I made these yesterday and the whole family loved them! They are so lemony and utterly delicious!! Thank you so much for this recipe 🙂

Thank you Victoria, I'm happy you enjoyed! 😊

Hi, I have three questions 😃 Is it ok to use powdered erythritol? What can I use instead of glucomannan powder and would this be suitable to freeze? Many thanks for your reply. 😀

Hi Alison here you go 😊
1) yes you can use powdered instead - just stick to the gram/oz values as powdered erythritol weighs less (per cup) so the result may not be as sweet if you use cup sizes.
2) Check out the tips in the intro - an extra egg yolk or some arrowroot powder will do the job.
3) I haven't tried it but I don't see why not. Nothing should separate/split if you then defrost it slowly in the fridge overnight. I hope this helps!