Keto Lemon Cake with Blackberry Mascarpone Frosting

This Keto Lemon Cake with Blackberry Mascarpone Frosting is moist and delicious with layers of lemon cake, lemon curd, and blackberry mascarpone frosting. It is the perfect low carb way to celebrate spring!

Looking for more low carb and keto dessert recipe ideas? Give these Peanut Butter Chocolate Easter Eggs or Keto Lemon Thumbprint Cookies a try!

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MORE KETO & LOW CARB RECIPES

Keto Sugar Cookie Bars | Keto Red Velvet Cheesecake Brownies

I realized that, since going low carb, I haven't posted any cake recipes. I do have a few regular ones from before but no low carb/keto ones.

So I decided to remedy that situation and with it being Spring I took inspiration from this cake over at Diet Doctors.

However, I am not a big make a cake for every occasion person. So, when I do make a cake I want it to pack a punch and leave an impression.

This is that cake, my friends!

I think we have established over the years that I am a lemon fan, followed quickly by blueberry. So I decided I wasn't going to go with that flavor combo for this cake. Instead, I decided to go with hubby's fave which is blackberry.

At first, I was just going to go with vanilla cake but I couldn't help myself and added lemon to the equation.

I have to say that I am super glad I did, as is everyone that has tried this cake!

INGREDIENTS NEEDED TO MAKE KETO LEMON CAKE WITH BLACKBERRY MASCARPONE FROSTING

Detailed measurements and instructions can be found on the printable recipe card at the bottom of the page.

INGREDIENTS

For the Lemon Curd

• Butter
• Besti Monk Fruit and Allulose Blend Powdered Sweetener
• Eggs
• Lemon juice

For the Lemon Cake

• Wholesome Yum Organic Coconut Flour
• Oat fiber
• Whey protein isolate
• Baking powder
• Salt
• Butter
• Besti Monk Fruit and Allulose Crystalized Sweetener
• Eggs
• Heavy whipping cream
• Vanilla extract
• Lemon juice
• Lemon zest
• Liquid sweetener

For the Frosting

• Heavy whipping cream
• Besti Monk Fruit and Allulose Blend Powdered Sweetener
• Mascarpone cheese
• Zest from a large lemon
• Sugar-free blackberry jam

For the Sugared Berries (optional)

• Water
• Besti Monk Fruit and Allulose Crystalized Sweetener
• Fresh blackberries

HOW TO MAKE KETO LEMON CAKE WITH BLACKBERRY MASCARPONE FROSTING

To Make the Lemon Curd

STEP 1
Melt the butter in a large microwave-safe bowl in the microwave for around 1 minute to 1 minute 30 seconds, or until fully melted.


STEP 2
Whisk in the sweetener, and lemon juice, and whisk until smooth, then whisk in the eggs.


STEP 3
Cook in the microwave on high in one-minute increments, whisking well after each minute until the mixture thickens enough that it coats the back of a spoon. The time may vary depending on your microwave's power.

STEP 4
Once thickened, transfer into an airtight container or jar, pressing plastic wrap onto the curd to prevent a skin from forming. Refrigerate for at least 2 hours until set.

To Make the Lemon Cake

STEP 1

Preheat the oven to 350 F.

STEP 2
Grease two 8-inch round cake pans with butter and line the pans with circles of parchment paper.

STEP 3
In a large bowl, whisk together the coconut flour, oat fiber, protein isolate, baking powder, and salt; set aside.

STEP 4
In a separate large bowl, use a hand mixer or stand mixer to whip the butter and granulated sweetener until well combined.

STEP 5
Add the eggs one at a time, beating well after each addition. Stir in the heavy cream, vanilla extract, lemon juice, lemon zest, and liquid sweetener by hand.

STEP 6
Add the dry ingredients and mix by hand until just incorporated.

STEP 7
Divide the batter evenly between the prepared cake pans. Bake for 20 to 25 minutes, until a toothpick inserted in the middle of a cake, comes out clean.

STEP 8
Let the layers rest for about 10 minutes before removing from the pans to cooling racks to cool completely.

To Make the Blackberry Mascarpone Frosting

STEP 1
In a large mixing bowl, whip the heavy whipping cream with a hand mixer.

STEP 2
As you whip the cream, add in the sweetener and extract.

STEP 3
In a medium bowl, whip together the mascarpone and blackberry jam until blended.

STEP 4
Add the mascarpone and blackberry jam mixture to the whipped cream and blend just until firm.

STEP 5
Stir in the lemon zest by hand and refrigerate until ready to frost the cake.

To Assemble the Cake

STEP 1
To assemble, slice each cake round in half horizontally.

STEP 2
Place one layer on a cake plate or cardboard round and pipe a ring of the frosting around the edge.

STEP 3
Spread 1/3 of the lemon curd on the layer inside of the ring of frosting. Use a light hand or a piping bag to cover the lemon curd with a layer of frosting.

STEP 4
Add another layer of cake followed by piping another ring of frosting and adding another 1/3 of the lemon curd and another layer of frosting.

STEP 5
Repeat until all four layers of cake are assembled.

STEP 6
Cover the top and sides of the assembled cake with the remaining frosting.

STEP 7
Cover and refrigerate for at least 8 hours or overnight before serving.

To Make the Sugared Berries

STEP 1
In a microwave-safe container, combine the water and 1/4 cup of sweetener. Stir together briefly.

STEP 2
Microwave for 1 minute to create a simple syrup.

STEP 3
Carefully remove from the microwave and stir in any remaining sweetener granules. Allow the simple syrup to cool for 5-10 minutes.

STEP 4
Once the syrup has cooled, dip your berries into the syrup and then roll into the remaining sweetener.

STEP 5
Set on a plate or pan and allow the syrup and sugar to dry and harden. This will take 5-10 minutes

STEP 6
Once the berries have hardened decorate the top of the cake with the sugared berries.

FAQS ABOUT KETO LEMON CAKE WITH BLACKBERRY MASCARPONE FROSTING

Do I have to use fresh lemon juice?

I always say that fresh is best! Plus you need lemon zest so juice those lemons.

Is oat fiber keto?

Oat Fiber is made from grinding the outer husks of oats. It's pure insoluble fiber, which doesn't dissolve in water and isn't broken down in the digestive tract, so it has zero net carbs which makes it perfect for a keto or low carb diet.

How do I store this Keto Lemon Cake with Blackberry Mascarpone Frosting?

Make sure the cake is covered well and store any leftovers in the refrigerator for up to 5 days. I have not tried to freeze this cake.

Last thoughts about Keto Lemon Cake with Blackberry Mascarpone Frosting

Berries are a low-carb diet's best friend when it comes to fruit/dessert. I learned that real quick. That is why this Mixed Berry Salad is one of my Spring and Summer go-to recipes for BBQs and get-togethers. I think I could eat my weight in berries if I tried.

Well, maybe I couldn't eat that much, but I could give it a good try!

The big bonus to being low-carb and living in Washington is blackberries grow wild around here. You can see people pulled over at the side of the road picking blackberries all of the time!

My husband's friend has tons of them on his property and brings me a huge bucketful every year. His only request is that I make him a batch of my Blueberry BBQ Sauce made with blackberries instead.

It is a great deal because it saves me a ton of money!

So thanks Doug! I can't wait to make this cake again! I might even send you some!!

MORE KETO AND LOW CARB DESSERT RECIPES

• Keto Blueberry Cheesecake Cookies
• Keto Strawberry Cheesecake Dip
• Mixed Berry Sugar-Free Frozen Yogurt
• Almond Flour Keto Lemon Cake
• Keto Lemon Pound Cake with Lemon Glaze
• Keto Lemon Cream Cake

If you like this recipe please leave a comment!

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