Luscious Keto Lemon Cake (Gluten-Free & Low Carb)

Lemons.  They have to be one of the best ingredients.  They brighten up everything and add a pop of wow to so many things.  This keto lemon cake is one example.  Take a simple vanilla cake, add some lemon, lemon curd, and creamy whipped cream frosting and you have a dessert that will knock your socks off.

If you love lemon, you will love this cake. 

This layered keto lemon cake is:

• Keto-friendly (watch your portion size)
• Low carb
• Gluten-free
• Refined sugar-free

A low carb lemon cake – Lemons make all the difference

So a few things you need to know about this low carb lemon cake.  Lemons really do make all the difference.  If you use bottled lemon juice, your curd and cake will have a bitter unpleasant after taste.  

Going through the effort of juicing your own lemons is worth it, trust me.  Fresh lemon juice makes a huge difference in the final dessert.

Myers lemons will work exceptionally well in this dessert if you can find them.   

TIP: Store your lemons in jars of fresh filtered water in your refrigerator.  This keeps them fresh for weeks longer and keeps them plump and juicy. 

What sweeteners Work best in this recipe?

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For the cake & whipped cream frosting…

Feel free to use your favorite 1:1 sweetener. 

Powered is preferred over granular, as it blends better and has a nicer texture.  At least I think so, but since different folks react to and prefer different sweeteners, I say use what you like best. 

My favorite low carb sweetener by far is So Nourished Monk Fruit Blend; I find it has almost no aftertaste at all. This sweetener is what I use in most of my baking recipes, including this one. Although the sweetener has erythritol, I find most finished recipes have no cooling sensation. 

Swerve and Truvia will work perfectly fine here as well as does any powdered erythritol or xylitol brand.  

For the low carb lemon curd…

The lemon curd is a bit different.  If you use erythritol or xylitol the curd will turn grainy when cold. It is not a pleasant mouthfeel in this cake.  

I used a combination of powdered erythritol monk fruit blend and allulose.  After a day in the fridge, the lemon curd only had a tiny little bit of graininess.  After 2 days the graininess was more pronounced.   If you used allulose only in this recipe, there would be no graininess at all even after a few days. 

Liquid sweeteners would work in the curd recipe, so if you have them feel free to use them. 

I get a lot of questions about Splenda, and although I do not use Splenda it would also work well in the curd recipe.   

A bit about the keto lemon cake batter

A few tips to make sure your lemon cake turns out perfect: 

• The cake batter for this recipe is going to feel thick.  It won’t pour into your cake pans, you will need to spoon it in and level it all out. 
• You will also want to prep your pans with parchment paper. 
• To prevent over-browning of the sides and bottom of your lemon cakes, be sure to wrap your pans with tin foil. 

For more low carb baking tips, check out our guide to baking with almond flour, and guide to replacements for xanthan gum!

Tips to make the low carb lemon curd filling

The sugar-free lemon curd filling is simple to make and only takes about 15 minutes from start to finish.   You do need to make the lemon curd in advance so it has a chance to cool before you add it to the cake layers. 

If you add warm lemon curd to the whipped cream frosting, it will melt the frosting, so make sure the lemon curd is cold before you add it to the layers.   

I made a double batch of curd when I made this recipe.   You only need 3 eggs for the amount of lemon curd in this recipe, so ignore the 6 eggs in the photo below. 

1. Add your sweeteners.  
2. Add 1/2 cup of fresh-squeezed lemon juice.  
3. Add the 3 whole large eggs.
4. Whisk everything together very well.
5. Add the cubed butter and cook over a medium heat whisking the entire time.  The curd takes about 7 minutes to cook.  You know the curd is cooked when you can see the whisk lines in the curd. Your time may differ depending on the power of your burner.  Do not cook on high, or you will scramble the eggs (not a great texture for the curd). 
6. Add to a bowl and cover with plastic wrap.  Make sure the plastic wrap touches the top of the curd to prevent a skin from forming.

Tips for the whipped cream frosting

Here are some tips to make sure your whipped cream frosting comes out perfect every time. 

1. In a stand mixer, or with a hand mixer, whip cold cream cheese until it becomes spreadable. 
2. Scrape down the sides of the bowl, to make sure all cream cheese bits are well blended.
3. Add the heavy cream, vanilla, and sweetener to the bowl and mix on low until whip cream starts to blend with cream cheese. Turn the mixer up and whip the mixture until soft and fluffy.

I like to use a 36% fat whipping cream for this recipe, but if you cannot get your hands on 36% whipping cream, any cream that you can whip will be perfectly fine.

Keep all the ingredients for your icing cold cold cold, you want your cream cheese to come out of a cold fridge and go directly into the bowl. Cube your cream cheese first to make it easier on your mixer. 

The frosting gets a bit stiff in the fridge but has a very similar mouthfeel to buttercream without an overly sweet bite. 

I only add 1/2 cup of sweetener which makes for a slightly sweet frosting, if you want it punchier and super sweeter, add more sweetener! 

Be careful to not overbeat your mixture.  Overbeating will cause everything to liquify.

This frosting works great for decorating cakes or even cupcakes. You can see how well it pipes by checking out my low carb roasted strawberry cupcakes. 

Assembly & Layering The Keto Lemon Cake

Ok full disclosure, I used a 6-inch pan for this recipe.  So the lemon cake is quite tall.  I used a cake dowel in the center to keep it from toppling over.   I love the presentation of a 6-inch cake, but for this recipe, I do believe that a standard cake pan would be better.  

Layering

1. Once the cake is cooled, we slice each round in half on the horizontal to create 4 cake layers. 
2. Place the first layer on your cake stand or plate.  Add a small dab of whipped cream frosting between the plate and the cake layer to prevent it from sliding. 
3. Add 3/4 of a cup of whipped cream frosting between each layer, and spread it thicker around the edges, to create a rim to hold in the lemon curd. 
4. Add 1/2 cup of lemon curd to the center of the whipped cream, and add a cake layer on top. Repeat until the last cake layer is added to the top.  
5. Use the remaining whipped cream frosting to decorate the outside of the cake.  I used a small star tip and added spirals all over the cake I made.  The whipped cream frosting does pipe well, but as it gets warm it starts to soften, and I find the piping gets a bit sloppy.  My advice if you want to decorate your cake perfectly is to keep the whipped cream frosting cold in the fridge, and only add a small amount to the piping bag at a time. 

Serving & storage suggestions

This keto lemon cake serves 12-14 easily making it perfect for a crowd or a holiday meal.    It does need to be stored in the fridge to keep the frosting intact, but it is delicious served cold.  This is one of those recipes that is better the next day! 

You can make the cakes in advance and freeze them.  The cakes store very well in the freezer for up to a month. The lemon curd can be made and stored in the fridge for up to a week.