Keto Chocolate Blackout Cake (Decadent Keto Chocolate Cake!)

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This is hands-down the most decadent keto chocolate cake you will ever make. Filled with creamy chocolate pudding, this low carb cake recipe takes inspiration from the famous Brooklyn Blackout Cake. Definitely worthy of a special occasion!

A slice of dark chocolate keto cake on a black plate on a black table.

Some occasions call for a truly over-the-top dessert. The sort of dessert that catches everyone’s eye and has the room buzzing with anticipation. Something deeply, darkly chocolatey, that looks so rich and moist you can’t believe it could possibly be low carb or keto friendly.

This keto chocolate cake recipe is it, my friends! It is the most amazing chocolate cake I have ever made in my life, keto or not. And I am not even sure what to call it. Keto Chocolate Blackout Cake is the best I could come up with.

I created this stunning sugar-free dessert for my 50th birthday. Because I think we can all agree that being alive on the planet for half a century is worthy of some serious chocolatey goodness.

I was in heaven from the first bite. My birthday felt truly special and this cake was no small part of that!

Keto Chocolate Blackout Cake on a white cake plate with a slice taken out of it and a strawberry on top.

Why you will love this cake

This cake is modeled after Brooklyn Blackout Cake, a recipe made famous by Ebinger’s bakery in Brooklyn during World War II. As always with keto friendly desserts, I had to take more than a few liberties to make it low carb.

It’s an amalgamation of three of my popular recipes. The cake layers come from my Keto Devil’s Food Cake, the filling is Keto Chocolate Pudding, and it’s frosted with super creamy Keto Chocolate Frosting. So it’s essentially triple the chocolate in one glorious recipe!

I won’t promise you that this is an easy cake to make. You don’t need any advanced skills but it does take time to make all the components and put them together. So leave yourself plenty of time and enjoy the process.

Because the results are absolutely worth the effort.

Ingredient Notes

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Almond flour: This is an almond flour based cake, but you can make it with coconut flour as well. Use the batter from my Keto Chocolate Cupcakes instead. The layers should take about the same amount of time to bake but keep your eye on them!
Sour cream: Sour cream gives the cake layers an incredible tenderness!
Cocoa powder: Use Dutch process cocoa powder for a deeper chocolate flavor. You can replace a little of with black cocoa if you want it even darker. I wouldn’t use more than a tablespoon or so in the cake and/or the frosting.
Protein powder: Using whey protein powder or egg white protein powder helps the cake rise properly and hold its shape.
Unsweetened Chocolate: Unsweetened chocolate gives the frosting a richer flavor and a creamy mouthfeel.
Sweeteners: I use Swerve Sweetener in the cake, the pudding, and the frosting. I also use a little allulose in the pudding to keep it from re-crystallizing. See the Expert Tips section for more sweetener options.
Keto thickeners: The pudding takes a little bit of glucomannan or xanthan gum so that it thickens properly.

How to make Keto Chocolate Blackout Cake

1. Prepare the pudding

I used a scaled down recipe of my sugar free chocolate pudding, making only two thirds of it. So I have listed the full instructions in the recipe. You will want to make this part first as it needs time to cool and thicken.

You can make it a full day in advance if you want to break up the process.

2. Make the cake layers

This cake uses the full recipe from the Devil’s Food Cake, minus the frosting. I refer you to that recipe for the full instructions for making the layers.

The cake needs to be completely cool before you attempt to slice the layers in half. If you make them in advance, all the better. Sitting in the fridge for a day helps them firm up more and allows for easier slicing. Wrap them up tightly so they don’t dry out.

3. Prepare the frosting

The cake is frosted with a modified version of my Keto Chocolate Frosting. I made a little more of it, and added additional chocolate and cocoa powder for a super rich, fudgy buttercream. Because of these modifications, I have listed the full instructions in the recipe below.

4. Assemble the cake

Now comes the fun part: putting all the pieces of the cake together!

1. The first step is to slice the layers of cake horizontally through the center to create four thinner layers of cake. Use a serrated knife and take your time!

2. Place one layer on a cake platter. Place some of the frosting in a piping bag and pipe a ring around the outside of the layer to create a barrier for the pudding.

3. Spread half of the pudding inside the ring. Top with another layer of cake, another ring of frosting, and the rest of the pudding. Place a third layer of cake on top.

4. Spread the remaining frosting over the top and sides of the cake. Take the fourth layer of cake and crumble it up in a bowl. Use about half of the crumbs and carefully press them into the sides of the cake.

5. Refrigerate about an hour to firm up the whole cake before slicing.

A spoon creating a swirl design on a keto chocolate cake.

Expert Tips

I highly recommend breaking up the process over the course of one or two days. You can make the pudding a day in advance and the cake layers can be made one or two days in advance as well. In fact, the cake layers are easier to slice when they have been refrigerated for a little bit. Be sure to wrap them up tightly so that they don’t dry out in the fridge.

Always line the cake pans with parchment to ensure that the layers come out of the pans easily. You still want to grease the pan, and then line them and grease the parchment as well.

Sweetener Options

You can use other sweeteners in every component of this keto chocolate cake, but there are a few things to keep in mind.

Allulose may make the outside of your cakes brown faster and almost seem a little burnt so keep your eye on them. The pudding will also be softer and take longer to firm up when made with just allulose.
The frosting requires a powdered sweetener to have the right structure and consistency. And other sweeteners like allulose and BochaSweet may make it softer so add the cream slowly and stop when it’s a spreadable consistency but it’s not goopy.

A slice of keto chocolate blackout cake with several bites taken out of it.

Frequently Asked Questions

Can you eat cake on a low carb diet?

Many people are surprised and delighted to find that they can enjoy cake on a low carb or keto diet. These days there are many delicious cake recipes that utilize alternative flours and sweeteners. I recommend starting with simple recipes like Almond Flour Cake or an easy Keto Mug Cake to get used to these new ingredients.

How many carbs are in a keto chocolate cake?

This luscious keto chocolate cake recipe serves 16 people and has 8.3g of carbs and 4.1g of fiber per serving. If you count net carbs, each slice has only 4.2g of carbs.

Why is it called Blackout Cake?

Ebinger’s Bakery created the Blackout Cake during World War II. Mandatory blackouts were required to protect the nearby Brooklyn Navy Yard. The cake contains multiple layers of dark chocolate cake with a chocolate pudding filling and plenty of rich, dark chocolate frosting. So the name is very fitting!

A slice of keto chocolate cake on a black plate with a strawberry and a fork.

More cakes you will enjoy

Keto Chocolate Blackout Cake Recipe

5 from 9 votes

Print Pin Rate

Course: Dessert

Cuisine: American

Keyword: brooklyn blackout cake, keto chocolate cake

Prep Time: 1

Cook Time: 1

Chill time: 4

Total Time: 2

Servings: servings

Calories: 357kcal

Equipment

2 8-inch round baking pans

Ingredients

Pudding

½ cup heavy whipping cream
½ cup almond milk Or another low carb milk
3 tablespoon Swerve Granular (or other granular sweetener)
2 tablespoon allulose
2 large egg yolks
¼ teaspoon glucomannan or xanthan gum
¼ cup cocoa powder
2 tablespoon butter cut into two pieces
½ teaspoon vanilla extract

Cake

1 recipe Keto Devil's Food Cake (just the cake, without frosting)

Frosting

3 ounces unsweetened chocolate chopped
½ cup butter softened
4 ounces cream cheese softened
⅔ cup Swerve Confectioners (or other powdered sweetener)
3 tablespoon cocoa powder
1 teaspoon vanilla extract
⅔ cup heavy whipping cream

US Customary – Metric

Instructions

Pudding

In a medium saucepan over medium heat, combine the cream, milk, and sweetener. Bring to a simmer, stirring occasionally.
In a medium bowl, whisk the egg yolks until smooth. Slowly add ½ cup of the hot cream mixture into the egg yolks, whisking continuously.
Slowly whisk the tempered egg yolks back into the saucepan of hot cream. Reduce heat to medium low and sprinkle with xanthan gum, whisking continuously.
Stir in the cocoa powder and cook until mixture thickens, 3 to 4 minutes, whisking continuously. Remove from heat and stir in the butter and vanilla extract until smooth.
Pour into a bowl, cover with plastic wrap, and refrigerate 2 to 3 hours.

Cake

Prepare the cake layers according to the instructions in the Devil's Food Cake recipe.
Let cool completely, then carefully slice each layer through the middle into two thin layers. (Tip: If you make the cake layers ahead of time, a few hours in the fridge help them firm up enough to slice more easily. Wrap them in plastic so they don't dry out).

Frosting

Place the chopped chocolate in a microwave safe bowl and melt in 30 second increments, stirring in between until smooth. Alternatively, you can melt the chocolate and butter together in a heat-proof bowl set over a pan of barely simmering water. Set aside to cool to lukewarm.
In a large bowl, beat the butter and the cream cheese together until smooth. Beat in the powdered sweetener and the cocoa powder until well combined.
Add the chocolate and vanilla extract and beat until smooth. The mixture will be very thick at this point. Add the cream a few tablespoons at a time until a spreadable consistency is achieved.

To assemble

Place one layer of cake on a cake platter and pipe a ring of chocolate frosting around the outside edge. This creates a barrier to keep the pudding from oozing out. Spread half of the pudding inside the ring of frosting.
Add another layer of cake on top and repeat with a ring of frosting and the pudding. Top with a 3rd layer of cake.
Spread the top and sides of the cake with the remaining frosting. If you want to make a swirl on top of the cake, place the cake on a turntable. Hold a spoon to the center of the frosted top and turn the cake. Move the spoon outward from the center as you turn.
Take the final layer of cake and crumble it up. Carefully press some of the crumbs into the sides of the cake (you will probably only use about half of the crumbs).
Refrigerate one hour to firm up before slicing.

Nutrition Facts

Keto Chocolate Blackout Cake Recipe

Amount Per Serving (1 slice (1/16th of cake))

Calories 357 Calories from Fat 282

% Daily Value*

Fat 31.3g48%

Carbohydrates 8.3g3%

Fiber 4.1g16%

Protein 9.4g19%

* Percent Daily Values are based on a 2000 calorie diet.

Keto Chocolate Blackout Cake

Why you will love this cake

Ingredient Notes