Keto Lemon Bars

These easy Keto lemon bars are a crowd-pleaser. They are super moist and just on the right side of zingy. Only 5 minutes prep and ready in just 40 minutes.

This recipe is a Sugar Free Londoner classic. It has been on the blog since 2019 and consistently gets 5-star reviews. "Delicious, light and fluffy," wrote a reader recently. She had just made it for the second time. "They come out perfect every time."

These keto lemon bars are definitely not traditional. In fact, when I first created this recipe, I was not aware that classic lemon bars have a shortbread crust and a lemon curd filling!

My recipe is essentially a keto lemon cake sliced into bars. Due to the addition of sour cream, it has a super moist crumb. I find there is a hint of baked cheesecake texture.

Classic or not, this is a truly delicious dessert experience. I am giving you plenty of topping options further down, including a sugar free lemon curd frosting.

Jump to:

• Ingredients
• Instructions
• Toppings
• Substitutions
• Recipe FAQs
• Storage
• More Keto Lemon Desserts
• Recipe

Ingredients

Here are the ingredients you'll need for easy sugar free lemon bars:

• Eggs - large. These must be at room temperature to help the cake rise better.
• Butter - Should be very soft. I warm mine in the microwave until it is almost melted.
• Sour Cream - room temperature. You could also use cream cheese.
• Lemon - We need both the juice and the zest. Make sure you buy unwaxed lemons. For me, 1 ½ lemons yielded ¼ cup lemon juice. For extra zing, you could increase the amount of lemon juice by up to 2 additional tablespoons.
• Almond flour - I've used ground almonds for this cake, which is equivalent to coarse/grainy almond flour. This helps with creating that super juicy sponge cake. Reduce the amount by ¼ cup (25g) for super fine almond flour.
• Baking powder - Check that it is fresh.
• Powdered sweetener - I used erythritol. However, this recipe will work just as well with Swerve, monk fruit sweetener blends, Bocha Sweet or allulose. Check that you are using a 1:1 sugar substitute.

See the recipe card for full information on ingredients and quantities.

Instructions

Let's make keto lemon bars! Here are step-by-step images. For more details, scroll down to the recipe card.

STEP 1

Beat the eggs until frothy. Then add the softened butter and the sour cream and blend in a food processor or with an electric mixer until combined.

STEP 2

Add the lemon juice, lemon zest and powdered sweetener and blend.

STEP 3

Last, add the remaining dry ingredients - almond flour and baking powder. Mix until smooth. Let the batter sit for a couple of minutes to thicken. It should be thick but pourable.

STEP 4

Line a small casserole dish or cake pan with parchment paper. I used a 9 x 6-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 smooth the top with a spatula.

STEP 5

Bake the cake on the middle oven shelf for 35-40 minutes or until a toothpick inserted comes out clean.

Toppings

I decided to keep it quick and simple and dusted powdered sweetener over the cake.

Here are more topping ideas:

Sugar Free Lemon Drizzle:

Mix 4 tablespoons lemon juice with 4 tablespoons powdered sweetener and drizzle over the cake.

Low Carb Lemon Glaze:

Stir together 4 tablespoons each of melted butter, cream, 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 ½ cup cream cheese, 4 tablespoons of powdered sweetener, a squeeze of lemon juice and grated lemon zest. Spread over the lemon bars and grate 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 heavy cream until stiff and fold in the cold lemon curd. Spread over the cooled cake and grate lemon zest on top.

Substitutions

Coconut flour: 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 plus an additional egg. A reader has tested this variation and reported that it works well.

Dairy-free: For dairy-free keto lemon bars, use coconut yoghurt or coconut cream in place of the sour cream. Also, use coconut oil or a dairy-free butter substitute.

Less fat: Use Greek yoghurt in place of sour cream.

Recipe FAQs

Storage

Store keto lemon bars in an airtight container at room temperature for up to 2 days or in the fridge for up to 5 days.

All almond flour cakes freeze well. I pre-slice this cake into bars and freeze them for up to 3 months. This way, I can defrost one slice at a time overnight.

More Keto Lemon Desserts

Tried this recipe? Give it a star rating below!

★ STAY IN TOUCH on FACEBOOK, PINTEREST and INSTAGRAM for more great food and join my NEWSLETTER for the latest updates.★

Recipe