Showcase the best of summer’s bounty with this beautiful Keto Lemon Blueberry Layer Cake. Tender and sweet, and bursting with flavor, it has a delectable sugar-free cream cheese frosting. And only 4.8g net carbs per slice!
Need more ideas for your summer zucchini? Check out this list of Keto Zucchini Recipes
Lemon and Blueberry: Classic Summer Flavors
This recipe has long been one of my summer favorites because it brings together so many fresh flavors. I tend to favor keto chocolate cake, but the light tangy sweetness of this Keto Lemon Blueberry Cake wins me over every time. And the zucchini adds wonderful moisture and nutrition.
I know that it can be hard to think about turning on the oven in the middle of summer. I get that, I really do, and I have many wonderful easy keto dessert recipes for those of you who just can’t bear the thought.
But if you’re a bakeaholic like me, sometimes you’ve just got to suck it up and bear it. Because you can’t bake gorgeous keto cakes like this one without a little heat. And sometimes nothing will do but a big layer cake with plenty of creamy frosting. So throw open those windows, blast the fans, or jack up the AC, kids. It’s going to get a little hot in here!
★★★★★
Nancy says: “I have made this cake several times and everyone always wants the recipe! It’s so delicious and moist and the lemon and blueberry flavors are such a wonderful taste of spring. Thanks, Carolyn!“
Ingredients and Substitutions
- Zucchini: This adds wonderful moisture and texture to the cake, along with a boost of nutrition.
- Almond flour: I really feel this cake works best with a finely ground almond flour. If you wish to use coconut flour, follow the basic amounts and instructions for my Keto Chantilly Cake.
- Protein powder: As with many baked goods, this helps the cake rise better and hold its shape. You can use whey or egg white protein powder. Plant-based may work as well but I don’t recommend collagen protein.
- Sweetener: I suggest using a granular erythritol-based sweetener in the cake and a powdered sweetener in the frosting. Please see the Sweetener Options for a more detailed discussion.
- Lemon: This cake recipes uses the zest and the juice. You can also bump up the lemon flavor with a little lemon extract.
- Blueberries: Fresh blueberries work best as they don’t bleed into the batter.
- Cream cheese: This is the base for the super creamy frosting!
- Heavy cream: A little heavy cream helps thin the frosting to a spreadable consistency.
- Baking staples: Butter, eggs, baking powder, vanilla, salt.
How to Make Keto Blueberry Lemon Cake
- Drain the zucchini: Salt and drain the zucchini in a sieve, then squeeze out as much moisture as possible.
- Prepare the batter: Whisk the dry ingredients together. Beat the butter with the sweetener until well combined, then beat in the eggs and extracts. Beat in the dry ingredients and lemon juice. Fold in the blueberries.
- Bake the layers: Spread the mixture evenly in two 8-inch round cake pans. Bake until golden brown and firm to the touch.
- Prepare the frosting: Beat the cream cheese and butter together until smooth, then beat in the sweetener, lemon zest, lemon juice, and cream.
- Frost the cake: Spread the top of the first layer with frosting, then add the second cake layer. Spread the remaining frosting over the top and sides.
- Garnish: Decorate with additional blueberries and lemon zest.
Carolyn’s Tips for Success
Squeeze the zucchini very dry so the cake isn’t mushy. You can do this with your hands, squeezing it in your palm and pressing it out in the sieve, or you can wrap it a tea towel and twist it.
Make sure the butter is properly softened! I find I sometimes have to give it a quick 10-second zap in the microwave, because room temperature is not always soft enough. It will beat more smoothly if it’s properly softened (but not melted), and become fluffier when you add the sweetener.
Don’t skip the grated lemon zest in either the cake or the frosting, as it gives the best flavor. You can also add some lemon extract to the cake, if you want more lemon flavor.
The frosting makes enough for the top of each layer and a thin “crumb coat” on the sides. If you want a fully frosted cake, I recommend increasing the frosting by about 30%. This will change the nutritional content.
Sweetener Options
For the cake layers, an erythritol sweetener that doesn’t contain any allulose will work best. Good brands to consider include Impact Sweetener or Lakanto. Sweeteners with any amount of allulose will cause the cake to brown too quickly and it may even taste burnt.
If you wish to cut down on erythritol, try using 1/4 cup and supplementing the sweetness with a highly concentrated sweetener such as pure stevia or monk fruit.
The frosting requires a powdered sweetener to have the right volume and structure. But both erythritol and allulose based sweeteners work.
More Delicious Keto Blueberry Recipes
Keto Lemon Blueberry Zucchini Cake
Equipment
Ingredients
Cake:
- 1 medium (196 g) zucchini, shredded, (about 200g)
- 1/4 tsp salt
- 2 1/2 cups (280 g) almond flour
- 1/2 cup (54 g) unflavoured whey protein powder
- 1 tbsp baking powder
- 1/4 tsp salt
- 1/3 cup (75.67 g) butter, softened
- 1/2 cup (95 g) granular sweetener, erythritol recommended
- 3 large eggs, room temperature
- 1 tbsp lemon zest
- 1/2 tsp vanilla extract
- 1/2 tsp lemon extract, (optional)
- 3 tbsp (45.65 g) freshly squeezed lemon juice
- 1 cup (148 g) blueberries, fresh works best
Lemon Frosting:
- 8 ounces (226.8 g) cream cheese, softened
- 1/2 cup (113.5 g) butter, softened
- 1/2 cup (95 g) powdered sweetener
- 2 tbsp freshly grated lemon zest
- 2 tbsp (30.43 g) freshly squeezed lemon juice
- 2 tbsp (30.43 g) heavy whipping cream
Garnish:
- fresh blueberries
- lemon zest
Instructions
Cake
- Place the zucchini in a sieve and sprinkle with the salt. Toss to combine. Let drain 1 hour and then squeeze out the zucchini to release as much moisture as possible.
- Preheat the oven to 325ºF and grease 2 (two) 8-inch round cake pans very well. Line the bottoms with parchment paper and grease the parchment.
- In a medium bowl, combine the almond flour, protein powder, baking powder and salt.
- In a large bowl, beat the butter with sweetener until well combined. Beat in the eggs one at a time, scraping down the sides of the bowl and the beaters as needed. Then beat in the zucchini, lemon zest, and vanilla extract.
- Beat in the almond flour mixture until well combined, then beat in the lemon juice. If your batter is quite thick, add a little water, 1 tbsp at a time, until a spreadable consistency is achieved.
- Gently fold in the blueberries. Divide the batter between prepared pans and spread evenly to the edges. Bake 30 to 40 minutes, until golden brown around the edges and the top is set to the touch.
- Remove and let cool completely in the pans, then run a sharp knife around the edges to loosen.
Frosting
- In a large bowl, beat the cream cheese and butter together until smooth. Beat in the sweetener until well combined, then beat in the lemon zest.
- Beat in the lemon juice and cream until well combined.
To Assemble
- Place one cake layer on a serving platter and spread the top with about 1/3 of the frosting. Add the second cake layer and spread the remaining frosting over the top and the sides.
- Garnish with additional fresh blueberries and lemon zest.
Nutrition
Are blueberries keto-friendly?
The reality is that any food can be “keto” if you eat small enough amounts of it. But blueberries, while super healthy and full of antioxidants, are not the most keto friendly fruit. 1 cup of raspberries has 15g of carbs and 8g of fiber, but blueberries weigh in at 21g of carbs and only 3.6g of fiber.
Again, it’s not that blueberries are bad for keto diets, but they do have more carbs than you’d think so it’s wise to be conscious of how many you consume. One of the main ways I reduced the carbs in this cake was by cutting back a bit on the blueberries. But don’t worry, you still get plenty of delicious ripe blueberries in every bite. I also cut back on the almond flour and added more protein for a lighter, fluffier cake!
Nutritional Disclaimer
Please note that I am not a medical or nutritional professional. I am simply recounting and sharing my own experiences on this blog. Nothing I express here should be taken as medical advice and you should consult with your doctor before starting any diet or exercise program. I provide nutritional information for my recipes simply as a courtesy to my readers. It is calculated using MacGourmet software and I remove erythritol from the final carb count and net carb count, as it does not affect my own blood glucose levels. I do my best to be as accurate as possible but you should independently calculate nutritional information on your own before relying on them. I expressly disclaim any and all liability of any kind with respect to any act or omission wholly or in part in reliance on anything contained in this website.
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Could I replace the whey protein powder with a TBS of homemade baking soda?
I am doubtful that would replace the whey properly but you are certainly welcome to try.
Made this tonight and it is out of this world fantastic! What a perfect delicious cake! This is so very flavorful, light and airy and a perfect combination. My husband and I both agree its one of our favorites! Thank you so very much!
I’ve got this cake in the oven now and it smells incredible! I used coconut flour instead if almond flour and I had to add quite a bit of unsweetened almond milk for it to even be spreadable. It seems really dense. I really hope it turns out okay! I can’t wait to try it!
You can’t replace almond flour with coconut flour without increasing the eggs significantly. Please see my tutorials on working with coconut flour and almond flour. https://alldayidreamaboutfood.com/2013/04/low-carb-basics-baking-with-coconut-flour.html And https://alldayidreamaboutfood.com/2013/02/low-carb-basics-baking-with-almond-flour.html
I can hardly wait to try this recipe! I love lemon and blueberry together!
This looks absolutely fabulous and I can’t wait to try it! I don’t have any Swerve. Can I substitute THM Sweet Blend? If so, how much?
Yummmy! is what I have to say. I made this scrumptious cake yesterday and it is delicious. I was worried that it was going to be dry because of how it looked coming out of the oven and I wasn’t sure if you measured the zucchini before or after squeezing it out. My worrying was in vain, we loved it and it is super moist. I went lighter on the sweetener because I’ve gotten used to things not too sweet, next time I will use even less.
This is a delicious recipe. I have made it twice now. The cake is light and delicious. Just a couple of thoughts. First, for my family this icing is way too sweet. I’m wondering if 1-1/4 cup of serve is accurate. I have found that Swerve is so sweet, I can usually cut it by half. For my second time making this, we actually used half the amount of sweetener for the icing, and a little less than 1 cup for the cake. It was perfect, for my family, this way. Second, for my second try at this, I wanted to use Xylitol and Swerve because I noticed the cooling effect the first time I made this recipe. This is just a preference. To add the Xylitol to icing, I melted the butter and dissolved it, otherwise the Xylitol would have had a grainy texture in the icing. It turned out perfect this way. Finally, I used “lemon extract” in this recipe and that also worked well. Your recipes are always delicious and I thank you for sharing them with me and my family.
Thanks for your thoughts, Lorri. Everyone differs in terms of taste and sweet tooth(s). Many readers find my recipes not sweet enough so I always try to find a middle ground. 🙂 But you may be a super taster of things like erythritol so use what works best for you.
Thanks again Carolyn. I’m going to try your “Victoria Sponge Cake” recipe next. 🙂
This cake is beautiful and absolutely delicious! We just finished eating our sample slices. Hubs, who has no need to watch his carbs and doesn’t like zucchini, gobbled his right up.
This will be a special occasion cake in the future. Yum!
Should the zucchini be rinsed before draining?
No need.
You have salt listed twice in the recipe. I’m sure it’s an error, yes?
No, that’s not an error. You salt the zucchini before you drain it and you also add a touch more salt to the batter.
This looks sooooo good Carolyn – I wish I had a slice right now. And, I have definitely had that experience of meeting someone in person and thinking they got switched with their online personality!
Sounds good. I don’t have Swerve, okay to substitute either Truvia or Splenda?
Truvia would be fine in the cake part but you really need a powdered sweetener for the frosting. Plus Truvia is sweeter than Swerve and doesn’t measure like sugar so I am uncertain of the amounts.
WOW! This looks so amazing. If only it wasn’t sweltering hot and humid here, I would turn my oven on right now and bake this immediately! It might have to wait for a cool spell but it will happen. Thank you Carolyn. You have made me very happy 🙂
I have been doing Trim Healthy Mama for a few months and have been so disappointed with any of the desserts I have tried. But I made this on Friday, and , wow, it is so VERY delicious! I will be definitely be trying your other low carb recipes soon. Thank you!
So glad it worked out and you loved it!
I’ve made so many of your recipes and I’ve never been disappointed! This one, however, absolutely knocked it out of the park! My hubby ate 2 huge pieces and I’ve never seen him do that. I normally stick to chocolate desserts but this is now one of my favorites. Thank you!
Yay, I am so glad!
Hi Carolyn, In your #4 instructions you say to beat the zucchinni. I use an electric hand mixer/beater. Is that what you mean by beat? The zucchinni will no longer be shredded. Or did you mean beat by hand? Please clarify for me. I’m excited to make this cake. Thanks!
Hi Holly… yes you beat it in with an electric mixer. But it will still be shredded. It does not break up simply by beating it in.
Oh thanks! ????
Made this cake yesterday and all I can say is “Delicious”. I baked it into cupcakes split them in half put icing in the middle and then put icing on top. Carolyn your the “BOMB”
Jess-
How many cupcakes did you make? And, how long did you bake them, and what temp?
I baked mine for about 32 minutes at 325. I moved the pans to the lowest rack in the oven during the last third of the baking time, since they were already quite brown around the tops/edges. A full recipe makes about 16 cupcakes.
They were PHENOMENAL!
Cupcakes, what a Great idea!
Hi! Did you use paper cupcake liners? I’m concerned about them sticking too much. Thanks!
Use parchment or silicone and you don’t need to worry at all. I love the parchment liners from Paper Chef – http://amzn.to/2xuOVQH
Thanks so much! I was scrolling through all the comments as I want to make these as cupcakes. Now I know I can!