Keto Lemon Bars

I’m a huge lover of lemon desserts, and the bright flavors of citrus fruits have always been my favourite options when it comes to having a sweet treat.

Anyway, I’d developed it for Beyond Flour, and it was wildly popular with my recipe testers (None of whom were gluten-free, themselves!), and - eventually - readers.

My keto dessert recipes have been pretty key to sticking to the keto diet, so I did up a low carb recipe for a lemon bar, based on that easy recipe.

While many low carb lemon bars out there have a shortbread crust topped with either a cake, Cheesecake, or gooey lemon filling / lemon curd layer - usually topped with powdered sugar - I went in a different direction with my keto lemon bars recipe.

These easy keto lemon bars have all of the texture - that gooey, chewy goodness you’d expect from a brownie - but instead of chocolate, it was a brightly flavoured citrus bar.

Finally, rather than a sprinkling of powdered sugar, I whipped up a quick, lemony frosting/glaze for it.

You know, really leaning in on the “lemon brownie” idea!

Recently, I started craving those tangy lemon bars ... so it was about time I posted my sugar-free lemon bars recipe!

New and Improved Keto Lemon Bars

This recipe has been reworked and re-photographed, as of January 7, 2024.

Among the changes:

1: The sweetener amount and type was changed. I’ve never been happy with how erythritol gave these a bit of a minty feel / taste, and this update with a different sweetener fixes that issue.

2. The protein powder was changed. I’ve been using vanilla flavoured protein powder for all of my baking lately. I find it gives a much better texture to the finished keto desserts, than the unflavored did.

3. I overhauled the process. Creaming the butter and sweetener was overkill - this new version is a 1 bowl lemon bar recipe, no hand mixer necessary!

4. Slightly increased the amounts of protein powder and butter.

If you liked the original recipe as it was - and aren’t ready to make the switch to allulose - no worries - I’ve got the original version of this recipe - and the photos that accompanied it - at the VERY bottom of this post.

Note: It is the one NOT in the recipe card.

How Many Carbs are in Keto Lemon Bars?

These keto treats are a great option for anyone with a keto lifestyle.

When it comes to carb count, these bars each have 49 grams of total carbohydrate, with 45 of those coming from the sugar alcohols. There is also 1 gram of fiber per bar - so about 3 grams of net carbs per bar!

Note: This is when you cut the 8 x 8 slab into 12 servings - they’re BIG servings.

You can easily get 16 regular size servings (4 x 4 in the pan), or even 24 small servings (cut the 12 bars in half), and these would be proportionately lower in overall and net carbs..

Keto Lemon Bar Ingredients

While some of the ingredients are pretty universal, simple ingredients available in most grocery stores - large eggs, butter, fresh lemons (for both fresh lemon juice and lemon zest), etc - there are a few that are more specific to keto baking.

Here’s a bit of information on those ones:

Almond Flour

Almond flour is foundational to SO many keto and low-carb baking recipes. I buy it in bulk, as I use it so often.

In general, you’ll have the best results from a fine grind flour that’s made from blanched almonds. That is to say, you shouldn’t see little bits of brown in the flour.

... That’s almond meal, but sometimes sold as almond flour.

Coconut Flour

Coconut flour is another super foundational ingredient when it comes to keto baking, and I often use it in conjunction with almond flour.

While almond flour doesn’t soak up / retain much in the way of liquid, coconut flour does. This contributes to the moisture content and overall texture of your baked goods - it’s a good complement for the almond flour properties.

Generally, you’ll use a LOT less coconut flour than you will almond flour, as a little goes a long way!

Vanilla Flavored Protein Powder

This recipe now uses Vanilla Flavored Whey Protein Powder, as mentioned earlier.

Personally, I keep a big canister of Revolution Nutrition's High Whey in Vanilla Cake on hand at all times, and use it in a TON of baked goods.

Use whatever vanilla protein powder that you like to drink, and fits your macros.

Sugar Substitute

The original recipe gave two options for keto sweeteners to use in this recipe -Swerve Granular Sweetener, or a Monkfruit/Erthyritol blend.

I have since switched to using allulose for all of my baked goods, and it’s been a huge improvement!

That said, I do still have two options for you:

This can be made with straight Allulose, or an Allulose-Monkfruit Blend.

Allulose by itself is slightly less sweet than regular sugar, and allulose - monk fruit sweetener blends tend to be more cup-for-cup substitutes.

They both taste a lot like regular sugar, but the you’ll need a bit more if just using straight allulose - both amounts are indicated in the recipe card.

Powdered Allulose

When it comes to the frosting, I have switched to using Powdered Allulose - Wholesome Yum's Besti Powdered Allulose is a popular option.

As with granulated, you can find this as straight allulose or as an allulose-monk fruit blend, but in this case, it doesn’t need different measurements - the frosting measurement is more about bulk, than sweetness level!

FYI: You can make your own by blitzing it in a high speed food processor until powdered.

That’s what I did when re-shooting this recipe, but I was impatient and didn’t go to all the way powdered.

That’s fine, you’ll just end up with a slightly grainier texture to your glaze, and need to microwave it a bit longer to liquify it.

Xanthan Gum

Xanthan gum is another ingredient I’ve brought with me from my regular gluten-free baking days.

While I used it exclusively with baking - it helps add some of the glue/stretch properties that gluten-free florus lack - these days, I also use it for a thickener for soups, sauces, etc.

A great thing to have on hand, when you’re living la vida low carb!

While the initial purchase may seem expensive, it lasts forever. You rarely use more than a teaspoon for a recipe.

Equipment

This is a very basic Low Carb Lemon Bars recipe, and most of what you’ll need are just measuring spoons, measuring cups, and something to mix it all together. No food processor - or even electric mixer - necessary!

That said, you’ll also need:

A Zester

I use a little handheld zesting plane for zesting citrus, but you can use the smaller grate side of a box grater.

I LOVE LOVE LOVE my Kitchenaid box grater, and will sing its praises to anyone who will listen.

There are cheaper options, but after decades with those cheap options? I'm obsessed with this one. A few extra dollars can make a world of difference sometimes!

A Juicer

I have a few different juicers here, and generally pick which to use based on how much I’m going to be juicing:

Cuisinart Pulp Control Juicer - I usually only use this one when I have a LOT of juicing to do.

A Reaming-Style over-Container Juicer - This isn’t the exact one I have at the moment, but the style is very similar. These are great - allowing you to manually juice into a container. This is the kind I use for recipes like this.

A Citrus Squeezer - This was my favoured type of juicer for small amounts of needed juice, until I started having tendon problems.

This style was easy to use, and the least amount of effort to wash, afterward!

Obviously, any of them will work just fine for this!

How to Make Keto Chewy Lemon Bars

The full recipe follows in the recipe card at the end of this post, here is the pictorial overview with additional info and tips:

Sugar Free Lemon Bars

First thing: Preheat oven to 350F (180C).

Grease an 8"x 8" square cake pan with vegetable shortening or baking spray.

I like to line the pan with parchment paper after spraying it. The spray helps the parchment stick to the baking dish, and the parchment helps with lifting the bars out.

Add melted butter, eggs, lemon juice and lemon zest to the bowl of dry ingredients, beat until smooth and well combined.

For best results, be sure to NOT overcook these. They firm up a bit more as they cool, so just cook them until they’re set in the middle. Overcooked bars are dry. Still tasty, but not the brownie-like texture they should be!

Allow bars to cool completely, before making the glaze:

Heat in the microwave for 15-20 seconds, and whisk again - it should be thick but spreadable.

Leftover Lemon Bars

Leftovers can be kept at room temperature - on a plate covered with plastic wrap, or in an airtight container - for several days.

More Low Carb Dessert Recipes

Looking to indulge your sweet tooth in a way that won’t spike your blood sugar? Here are some keto recipes to try!

Biscotti
Carrot Cake
Cheesecake
Chocolate Chip Cookies
Chocolate Truffles
Cream Cheese Mints
Creme Brulee
Easy Keto Lemon Curd
Fudgy Brownies
Key Lime Cheesecake
Ladyfingers
Lemon Tart
Low Carb Holiday Desserts
Marbled Pumpkin Cheesecake Brownies
Protein Chocolate Cookies
Raspberry Coconut Bars
Raspberry Truffle Tart
Sugar-Free Jello
Tiramisu
Traditional Chocolate Mousse

... but wait, there's more! We have a whole Low Carb Dessert Recipe section! Check it out!

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Original Recipe and Photos

Here is the original recipe, from before the 1/7/2024 overhaul:

Lemon Bars

6 tablespoon Butter, room temperature
¾ cup 1:1 Sugar substitute (Like an Erythritol Monkfruit Blend)
3 Large eggs
Juice of one lemon
Zest from two lemons
½ cup Almond flour
¼ cup Unflavoured protein powder
¼ cup Coconut flour
½ teaspoon Baking powder
½ teaspoon Xanthan gum
½ teaspoon Salt

Glaze:

1 ½ cup Swerve powdered sugar
2 tablespoon Lemon juice or more as needed.
pinch Salt

Instructions

Preheat oven to 350F (180C). Grease an 8"x 8" square cake pan with vegetable shortening or baking spray.

Cream together butter and sugar substitute until pale and fluffy.

Add eggs, lemon juice and lemon zest, continue to beat until well incorporated and smooth.

In a separate bowl, whisk together flours, protein powder, baking powder, xanthan gum and salt. Add this dry mix to the wet ingredients, stir gently until everything is well distributed.

Transfer batter to prepared baking pan, spreading evenly. Bake for 20-25 minutes, or until set in the middle. Do not over cook!

Allow bars to cool completely, before making the glaze:

Glaze Instructions

Whisk together powdered sugar, lemon juice, and salt. It should be very thick. Heat in the microwave for 15-20 seconds, and whisk again - it should be thick but spreadable.

Spread frosting over cooled bars, allow to set up before slicing and serving.

27 grams of the per-serving carbs come from the erythritol - sugar alcohol - so the net carbs on each bar = 3.