Keto Lemon Bars
Published July 26, 2019 • Updated February 24, 2026
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These low carb lemon bars have a buttery almond flour crust and a smooth, tangy filling I've tested more times than I can count. Around 3g net carbs per bar, and the crust holds up even after sitting in the fridge overnight.
I made these for a local fundraiser dessert auction a couple of years ago, and they ended up being the top-bid item of the entire event. Almond flour cookies, brownies, all of it. The next year, the same buyers came back asking if I brought ‘those lemon bars’ again. That’s when I knew this recipe was permanent.
Each bar comes in at around 3g net carbs, which is part of why I reach for this recipe when I need a dessert that works for everyone at the table. The crust is almond flour with a sprinkle of unsweetened coconut flakes, and that combo gives you a buttery base with a real crunch that holds under the filling. Even if coconut isn’t your thing, you’ll barely notice it. It’s there for texture, not flavor. I’ve made these without the coconut too, and the crust comes out softer, more like a sandy shortbread. Still works, but I prefer the version with them.
The filling is bright and tart without being sour. I use powdered sweetener (not granular) because it dissolves completely into the curd and gives you that smooth, clean texture. One tablespoon of arrowroot thickens the entire batch, and per bar, it adds less than a gram of carbs. If you’ve baked my pie crust, you already know almond flour bakes into something sturdy, and that same principle applies to this base.
I actually think these taste better the next day once the lemon curd has settled and chilled. You can assemble and bake them the night before without the crust getting soggy. The almond flour base doesn’t absorb moisture the way regular shortbread does, which is one of the reasons I keep making them. Slice them cold out of the fridge and the cuts come out cleaner too.
These are a solid make-ahead keto dessert for parties, especially alongside something richer like chocolate mousse or peanut butter pie. If you’re building a low carb dessert spread, pair them with s’mores or strawberry shortcake kebabs for contrast. Citrus next to chocolate is always a good call.
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The Crust Ingredients
1 ½ cups almond flour -
1/4 cup sugar free sweetener
-
1/2 cup coconut flakes, unsweetened
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4 tablespoons (½ stick) melted unsalted butter
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1/2 teaspoon salt
-
1 teaspoon lemon zest
The Lemon Curd Ingredients
-
4 eggs
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1 ¼ cup powdered sugar-free sweetener
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3/4 cup of lemon juice (if you prefer it less tart, try 1/2 cup)
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1 tablespoon arrowroot powder
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1 teaspoon baking powder
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pinch salt
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zest from one lemon
Step by Step Instructions
Step by Step Instructions
Get a small bowl
In a small bowl, combine all the ingredients for the crust and mix until combined.
- 1 ½ cups almond flour
- 1/4 cup sugar-free sweetener
- 1/2 cup coconut flakes, unsweetened
- 4 tablespoons (½ stick) melted unsalted butter
- 1/2 teaspoon salt
- 1 teaspoon lemon zest
Bake it
Bake at 325°F for 10-12 minutes. Set aside to cool and increase the oven temperature to 350°F.
Lemon curd
To make the filling, mix the ingredients for the curd in a bowl.
- 4 eggs
- 1 ¼ cup powdered sugar-free sweetener
- 3/4 cup of lemon juice (if like it less tart, try 1/2 cup)
- 1 tablespoon arrowroot powder
- 1 teaspoon baking powder
- pinch of salt
- zest from one lemon
Nutrition disclaimer
The nutrition information provided is an estimate and is for informational purposes only. I am a Doctor of Pharmacy (Pharm.D.); however, this content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified health provider before making any lifestyle changes or beginning a new nutrition program.
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Get My Macros + Recipes →Frequently Asked Questions
Why does my lemon filling turn out grainy?
I ran into this the first few times I tested this recipe, and it always came down to the sweetener. Granular sweetener doesn't dissolve fully in the curd, so you end up with a gritty texture you can feel on your tongue. I switched to powdered and the filling came out completely smooth. If your sweetener is granular, pulse it in a blender for about 30 seconds before using it.
Can I make these the night before?
I do this all the time, and they're actually better for it. The almond flour crust doesn't absorb moisture the way regular shortbread does, so it stays firm even after sitting under the lemon filling overnight. I bake them in the evening, let them cool, cover, and refrigerate. The next morning they slice cleaner and the flavors are more settled.
Does allulose work in this recipe?
I've tested these with both allulose and erythritol. Allulose gives a smoother mouthfeel and doesn't have that cooling aftertaste some people notice with erythritol. It also browns a little more in the oven, so your crust may come out slightly darker. Both work well for keto baking, but if texture is your priority, I'd go with allulose.
How do I know when the lemon filling is done baking?
I pull mine when the center still jiggles slightly, like a gentle wobble when you tap the side of the pan. The edges should look set but the middle shouldn't be firm yet. It continues to set as it cools, so if you wait until the center looks solid in the oven, you'll overbake it and the texture goes rubbery. I've learned this the hard way.
How do I thaw frozen lemon bars without ruining the texture?
I move them from the freezer to the fridge the night before I want to eat them. Slow thawing keeps the filling smooth and prevents it from weeping. If you thaw at room temperature, the outside defrosts faster than the center and you get a soggy layer on the bottom. About 8 hours in the fridge and they taste almost like I just made them.
What can I use instead of almond flour?
I've made the crust with sunflower seed flour for a nut-free keto version, and it works. The texture is a little different, more dense and less crumbly, but the bars still hold together and taste great. A seed flour blend is another option. I'd avoid coconut flour here because it absorbs too much moisture and the crust comes out dry.
Can I make these dairy-free?
I've swapped the butter for coconut oil and the bars turned out well. The crust has a slightly different flavor, a little more coconut-forward, but the lemon filling masks most of it. A dairy-free butter alternative works too if you want to keep the buttery taste closer to my original version.
Can I skip the arrowroot powder?
You can, but the filling will be thinner and take longer to set. I've tested it without and the bars still work, they just don't slice as cleanly. My swap is about a teaspoon of xanthan gum, which thickens the curd the same way. Between the two, I reach for arrowroot because I like how it sets, but xanthan gum is the easier pantry find for most people.
Browned the butter instead of just melting it and the almond flour crust got this deep, nutty richness that makes the tart filling feel more intentional by contrast. Four stars because I'd push the sweetener in the filling up slightly for my taste, but that crust alone is worth the tweak. If you try it, watch the butter around the 3-minute mark, it turns on you fast.
I want to make these in a muffin tin instead of the square pan (bringing them to a work thing next week and individual portions just make more sense than trying to slice and serve) but I'm not sure if the almond flour crust is going to hold its shape when you pop them out or just crumble everywhere. Does the bake time change much too, or is that 10-12 minute window still roughly what I'm aiming for?
My wife has been keto-adjacent for years (supports the lifestyle, doesn't do it herself) and she pulled one off the cooling rack before I even had a chance to dust them with powdered sweetener, and her first question was whether I'd used real sugar because the filling had that tart, silky set she associates with proper curd. I told her arrowroot, almond flour crust, sugar-free the whole way through, and she got this look like she was running the ingredient list in her head trying to find the catch. She didn't find it. I've been using the full 3/4 cup of lemon juice (I know that sounds aggressive but back off even slightly and you lose the thing that makes these taste like lemon bars instead of just lemon-flavored dessert), and I let them chill a full 3 hours before slicing, which gives you that clean bakery-style cut rather than the sloppy mess you get from cutting too early. Fourth time making these and they're becoming a spring thing in our house now.
Making these next weekend and wondering if I can assemble Saturday night. Will the shortbread get soggy sitting under the lemon filling overnight, or is same-day the only way?
The crust holds up overnight, especially in the fridge. Slice them cold and the cuts are actually cleaner than same-day. The almond flour base doesn't go soggy the way regular shortbread does.
made these yesterday and the arrowroot powder really thickens the filling. does the crust recipe work without coconut flakes? i have some but wondering if i can skip them next time
You can skip them but the crust will be softer, more like a sandy shortbread. The coconut adds texture and helps it hold together. Still works without though.
I absolutely loved this! The buttery crust pared with the tart lemon curd was so delicious. I added a tiny bit more lemon zest and minced up some basil and added that too. I know it sounds odd, but it gave the bars a brighter flavor. I might try a hint of orange zest next time.
Basil in lemon bars. I've never tried that but now I'm curious how the herb flavor worked with the sweetness. Orange zest would be good too, I do orange in the crust sometimes.
Going to try these tomorrow for my 80 th birthday treat...ty
80th birthday calls for lemon bars. Pull them when the center still jiggles, they firm up as they cool.