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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This was a huge flop for me!! I generally have great success with keto baking. BE CAUTIOUS!!!!!!!
Luscious!
Carolyn, this lemon blueberry cake was absolutely delicious! I made it for the first time and it was spectacular. I took it to a potluck and returned home with barley any crumbs. Everyone thought it was simply delicious. Thank you for all of your efforts in making keto baking accessible, easy to recreate and yummy. I wanted to say delicious again but I had already said two times. Oh well, what’s one more time – delicious!
So glad you liked it! This is one I want to make again and get new photos. 🙂
Waiting on zucchini to finish resting, then ready to bake with freshly picked blueberries! I’m guessing this cake needs to be stored in the fridge? And for how long can it last before freezing? Thanks!
Thank you for the recipe. I am wondering if you can omit the zucchini? Thank you
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!
can this be made 1 day before I have to serve it. looks amazing
Yes, one day should be fine.
I just made this yesterday evening – it was the best low carb cake ever! I didn’t feel like baking it in 2 pans and frosting it, so I just spread the batter in a greased 11” x 7” glass pan and it came out perfect! Sooo moist and delicious! Thank you Carolyn!
Absolutely delicious with hand picked East Texas blueberries! It’s Halloween, but I picked up zucchini at the Farmer’s Market and had some frozen berries, so this recipe hit the spot!
I made this cake. Although it is VERY tasty, it was a little dry almost like cornbread. Is that how it is supposed to be, or did I do something wrong? Part of me felt like I should have added a little more liquid but I wasn’t sure. What is the consistency of the batter supposed to be? Like regular cake batter? Maybe that answer would help me.
That means you over-baked it, I think. The recipe already describes what it should be like ” If your batter is quite thick, add a little water, 1 tablespoon at a time, until a spreadable consistency is achieved.”. Spreadable… not pourable. Hope that helps!
Thank you Carolyn. That is probably the problem. I have a new stove that has a convection oven. Still trying to get the hang of it. I think it bakes faster than normal oven heat.
Ooooh, if using convection, make sure you turn down the heat! At least 25 degrees….
I made cupcakes with this recipe and just divided among 16 cupcakes only to make individual servings easier for me ! Oh my gosh❣️ I absolutely LOVE this recipe!!!
What a great idea! I’m going to make it that way too