These easy, delicious keto lemon bars are a perfect low-carb treat. A buttery almond flour shortbread crust is topped with a bright lemon curd for a dessert that satisfies lemon lovers without the sugar.
If you enjoy sugar-free lemon curd, you’ll love these keto lemon squares—the topping is pure lemon flavour, balanced so it isn’t overly tart or too sweet. Chilled overnight, these gluten-free, low-carb lemon bars capture the zesty charm of traditional lemon bars while keeping carbs and sugar low.
Before trying these, we hadn’t experienced lemon bars much since they’re an American classic and less common in the UK. After the first bite we were hooked — they deserve to be a regular dessert in the rotation.
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Can you have lemons on keto diet?
Lemons contain small amounts of natural sugar but are relatively low in net carbohydrates. One fluid ounce (about 30 ml) of lemon juice has roughly 1.5 grams of carbs, so the quantity used in recipes like these lemon bars fits comfortably within typical ketogenic macros.
These keto lemon bars have just 4g net carbs per square, compared with up to 20g carbs for a traditional lemon bar, making them a much lower-carb option.
Ingredients
With simple keto-friendly ingredients you can make refreshing low-carb lemon bars—perfect for summer or any time you crave a citrus dessert.
- Almond flour – use finely ground almond flour for a tender crust and smooth filling.
- Fresh lemon juice – freshly squeezed gives the best bright citrus flavor.
- Lemon zest – use unwaxed lemons and wash thoroughly before zesting.
- Sweetener – allulose works well for these; monk fruit or erythritol blends also work.
- Xanthan gum – helps thicken the filling and gives a smooth texture without starch.
- Eggs – use room temperature eggs for the best emulsion and set.
How to make keto lemon bars
This recipe is straightforward but benefits from being made the day before serving. Make the lemon filling while the base bakes and chill overnight for best texture and flavor development.
Combine the base ingredients until evenly mixed.
Form the mixture into a dough— it will be slightly sticky but pressable.
Press the dough evenly into an 8-inch square tin lined with parchment paper.
Bake the base for about 10 minutes until lightly golden.
Whisk the eggs, egg yolk, lemon juice, zest and sweetener until smooth.
Stir in almond flour and xanthan gum for body and stability.
Pour the filling over the hot base and return to the oven.
Once chilled and fully set, cut into squares and serve.
Keto Lemon Bar Recipe Tips
Unflavored gelatin, ground chia seeds or ground flaxseed can replace xanthan gum if you prefer. Use them in approximately the same quantity to achieve a similar binding effect and texture.
Avoid overbaking—the filling should be just set and slightly jiggly in the center when you remove the pan. Overbaking will dry the bars and make them crumbly.
For a pretty finish, dust the tops with powdered allulose or a mix of powdered sweetener and lemon zest before serving.
Storage
Store leftover lemon bars in an airtight container in the refrigerator for up to five days. They also freeze well for longer storage.
Freezing
Allow bars to cool completely to room temperature before freezing. Cut into portions so you can thaw only what you need. Wrap individual portions in parchment or plastic wrap, then place them in an airtight container or freezer bag with as much air removed as possible to avoid freezer burn.
Keep the container flat in the freezer so the bars retain their shape.
Thawing and serving
Thaw frozen bars in the refrigerator overnight or at room temperature for a few hours. Once thawed they should retain the same bright lemon flavor and creamy texture as when freshly made.
Serve chilled or at cool room temperature for best results.
More keto lemon dessert
If you love lemon but want to avoid sugar, try these other low-carb lemon desserts from the same collection.
Lemon Mousse Cake
Lemon Swiss Roll
Lemon & Lime Ricotta Cake
Keto Baked Lemon Cheesecake
Keto Lemon Bars
Angela Coleby
Pin Recipe
Use the unit conversion buttons in the recipe card to toggle between US and metric measurements.
Ingredients
Base
- 1 ½ cups almond flour
- 3 tablespoons allulose or other sweetener
- 3 tablespoons butter, melted
- 1 teaspoon lemon zest
- ¼ teaspoon xanthan gum
- 1 medium egg
Filling
- 5 large eggs
- 1 medium egg yolk
- ½ cup allulose or other low-carb sweetener
- 1 cup lemon juice
- 1 tablespoon lemon zest
- ¼ cup almond flour
- ⅛ teaspoon xanthan gum
Instructions
Make the base
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Preheat oven to 180°C (350°F). Line an 8-inch square baking tin with parchment paper.
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In a bowl, mix the dry base ingredients. Add melted butter and the egg, then combine into a sticky dough.
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Press the dough into the prepared tin and smooth the surface.
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Bake the base for about 10 minutes until lightly golden, then remove from the oven.
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Pour the filling over the hot crust and return to the oven.
Make the filling
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While the base bakes (or beforehand), whisk together eggs, egg yolk, lemon juice, lemon zest and sweetener until smooth.
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Stir in almond flour and xanthan gum until fully combined.
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Pour the filling over the hot base and bake 15–18 minutes, until the center is just set and slightly jiggly.
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Turn off the oven, prop the door open slightly and let the pan cool inside for about 1 hour.
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Refrigerate the pan for at least 4 hours, preferably overnight, until fully chilled and set.
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Cut into squares, remove from the tin and dust the tops with powdered sweetener if desired.
Notes
Nutrition
Nutrition information is an estimate provided by an online nutrition calculator.
