This triple layer keto mousse cake is a glorious sugar-free dessert recipe. It combines a brownie base with creamy keto chocolate mousse, all topped off with airy espresso mousse.
This takes keto baking to a whole new level!
You may have noticed that I have a thing for rich, creamy chocolate desserts. And perhaps you’ve figured out by now that I adore coffee and coffee-flavored treats.
So it only makes sense that I bring these two passions together from time to time. Keto tiramisu is a prime example, as are my keto chocolate truffles with espresso.
But this stunning keto mousse cake may be the crowning achievement of keto desserts. It’s so creamy, so light, and yet so rich. Two delicious layers of mousse on top of a fudgy brownie crust. I dream about this stuff!
Easy Keto Mousse
There are any number of ways to make keto mousse. There is the traditional French style mousse, which involves whipping egg whites to stiff peaks and folding them into the chocolate mixture.
And then there are easier versions based on cream cheese and whipped cream. My famous 5 Minute Keto Peanut Butter Mousse falls into this category, as does my Keto White Chocolate Mousse.
But this keto mousse cake employs a third method that uses gelatin to set a whipped cream mousse. It’s ideal for mousse that needs to maintain its shape, such as in a mold or a cake. And it’s quite easy to do, so don’t be intimidated by all the layers of this cake. Let me walk you through it, step by step!
How to make Triple Layer Keto Mousse Cake
1. Prepping the Pan
I wanted this cake to be taller and more impressive looking, so I chose to use an 8-inch cake pan. You could also do a 9-inch pan, but the layers will be more spread out and the brownie base will cook through faster.
You can’t use any old cake pan, however, or you will never get your cake out in once piece. It must be a pan with removable sides. Choose a springform pan or a pan with a removable bottom.
Grease the pan well, so the brownie layer doesn’t stick, and line the bottom with parchment so it’s easier to transfer the cake to a cake plate.
2. Brownie Base Layer
Keto Chocolate Espresso Mousse Cake utilizes keto brownies as the crust. My favorite brownie recipe contains almond flour, but you also use coconut flour brownies if you want to be nut-free.
Because a round pan has less total area than a square pan of the same width, the brownies will take a bit longer to bake through than normal. Keep your eye on them, and remove them from the oven when the edge are set but the center is still a tiny bit jiggly.
I also recommend setting the cake pan on a cookie sheet before baking, especially if using a pan with a removable bottom. This keeps any oils that drip out during baking from messing up the bottom of your oven.
3. Chocolate Mousse Layer
First, make sure to melt the chocolate completely, but don’t let it get too hot or it will seize. I recommend melting with a little butter or coconut oil to smooth it out.
Bloom the gelatin in some water in a saucepan, and and then heat it gently with a little of the cream. Once the gelatin dissolves, whisk this into the bowl of melted chocolate.
Then whip the remaining cream with sweetener and vanilla until it holds stiff peaks. Fold this carefully into the melted chocolate until no streaks remain. Pour over the crust and refrigerate.
4. Espresso Mousse Layer
Bloom the gelatin again in some strong coffee or espresso, and then gently heat until the gelatin dissolves. Let this mixture cool to lukewarm.
Whip the cream with the sweetener and vanilla until it holds stiff peaks. Then stir in the espresso mixture until no streaks remain and pour this over the chocolate mousse layer.
Refrigerate the cake until completely set, then dust the top with cocoa powder.
Frequently Asked Questions
Yes, you can still make this cake. Just know that your brownie base will be thinner and thus will bake through faster. So set your timer for 15 minutes and check on it frequently.
The finished cake will also be lower and wider than the one featured here.
Yes, certainly! You can either swap the almond flour in the brownies for sunflower seed flour, or you can use my coconut flour brownie recipe.
You really need a powdered sweetener to give the mousse some structure without grittiness. Other powdered sweeteners may work but I do find that things made with allulose tend to take a long time to set properly.
This cake keeps well for up to 5 days. Store in the refrigerator at all times in a covered container, with any cut edges covered with plastic wrap to keep it from drying out.
I have not tried freezing this recipe.
More keto coffee recipes
- Easy Keto Frappuccino
- Chocolate “Kahlua” Cake
- No Churn Keto Coffee Ice Cream
- Sugar-Free Coffee Liqueur
- Keto Espresso Shortbread Cookies
- Mocha Latte Cheesecake Bites
- Frozen Mocha Mousse Bars
Keto Mousse Cake Recipe
- 1 8-inch cake pan with removable bottom OR 8-inch springform pan
- 1 recipe Ultimate Keto Brownies
Chocolate Mousse Layer
- 2 ounces unsweetened chocolate chopped
- 1 tbsp butter
- ¼ cup water
- 1 ¼ teaspoon grassfed gelatin
- 1 cup heavy whipping cream divided
- ⅓ cup Swerve Confectioners
- ½ teaspoon vanilla extract
Espresso Mousse Layer
- ⅔ cup espresso or strongly brewed coffee cooled
- 1 ½ teaspoon grassfed gelatin
- ¾ cup heavy whipping cream
- ¼ cup Swerve Confectioners
- ½ teaspoon vanilla extract
- 1 tablespoon cocoa powder
- Fresh raspberries
- Preheat the oven to 325ºF and lightly grease an 8-inch springform pan or a cake pan with a removeable bottom. Line with parchment paper and grease the paper. Set the pan on a rimmed baking sheet.
- Prepare the brownie batter according to the directions and spread in the prepared baking pan. Bake 20 to 25 minutes, or until the edges are set but the center is still a little jiggly. Remove and let cool completely.
Chocolate Mousse Layer
- In a large microwave safe bowl, melt the chocolate with the butter on high in 30 second increments, stirring in between until smooth.
- Place the water in a small saucepan and sprinkle the gelatin over top. Let bloom 5 minutes, then place the pan over medium low heat and add ¼ cup of the heavy cream. Stir until the gelatin is dissolved, but do not let it come to a boil. Slowly whisk into the chocolate mixture.
- In a large bowl, beat the remaining cream with the sweetener and vanilla extract until it holds stiff peaks. Stir about ¼ of the whipped cream into the chocolate to lighten it, then fold in the remaining cream until smooth.
- Spread this mixture over the cooled cake and refrigerate while making the espresso mousse.
Espresso Mousse Layer
- In the same saucepan as above, place the espresso. Sprinkle with the gelatin and let bloom 5 minutes, then place over medium low heat. Stir until the gelatin is dissolved, but do not let it come to a boil. Remove from heat and cool to lukewarm.
- In a large bowl, beat the cream with the sweetener and vanilla extract until it holds stiff peaks. Gently fold in the cooled espresso mixture until well combined.
- Spread over the chocolate mousse in the pan and refrigerate until firm to the touch, 1 to 2 hours.
- Use a sifter to sprinkle the top of the cake evenly with cocoa powder.
To unmold the cake
- Warm up a small sharp knife by either running boiling water over it or holding it over a gas flame for a few seconds. Run the knife around the inside of the pan to loosen the cake.
- Release the pan sides for a springform pan. If using a cake pan with a removeable bottom, simply push the bottom up to release the cake.
- Serve with fresh berries.
Stacey Kane says
Can I use two little 4” x 2” springform pans instead of one large, and if so, with the baking time be different?
If I use regular gelatin, will the flavor or texture be different? It’s not easy to find small containers or bags of the grass fed gelatin and it’s extremely costly.
Thanks so much Carolyn.
Is the gelatin a must? I don’t have any so is there a good substitute? Thanks. I love your recipes
Yes, it’s a must. You can’t set this mousse without it.
This looks delicious. I would love to make this for my diabetic mother, but she hates coffee. What could I sub in the espresso layer?
Just go with vanilla. Use 2/3 cup almond milk and add extra vanilla.
Made this for a birthday and everyone swooned. Even my son, who is picky about keto desserts, raved about it and ate every bite. Beautiful presentation and not nearly as difficult to make as might look.
So glad to hear it!
Vikki Bailey says
I made this gorgeous cake for my birthday a few months ago and it was a huge hit in my family of 4. Now everyone is requesting it for their birthdays as well as other special occasions. I’m getting ready to make it again. We have four adults here, all on keto/low carb for a few years now, and we loooove your recipes and enjoy them several times a week. Thank you for your hard work Carolyn. I can always rely on your recipes to be yummy and appealing. You have truly made our lives so much better!
I am SO glad you gave this one a shot!
My husband made this for me for my bday. It was really good.
Wow, I am impressed that he did!
Very nice recipe. The kids loved it.
Does the brand of gelatin matter in this recipe?
I am using the Now brand (I live in Italy, and it’s the only beef gelatin I found, otherwise we have pork gelatin in sheets), but it seems to me that the mousse it’s not thickening after various hours in the fridge.
Maybe I should have increased the amount of gelatin? (actually, on a first glance I read “tablespoon” instead of “teaspoon”).
Oh dear, that’s concerning. And yes, the brand may make a difference and it may have needed more. If worst comes to worst… freeze it and eat it like a frozen mousse cake!
Oh also… what sweeteners did you use? That can affect the consistency as well.
After a whole day in the fridge, the mousse did set, in the end! 😀 It is very soft, however (in particular the coffee layer), so maybe next time I will increase the gelatin a little.
As a sweetener, I used confectioner’s Sukrin, which is like confectioner’s Swerve (erythritol + stevia).
All in all, this mousse cake is awesome, the taste is really divine! So I will definitely make it again, maybe with some tweaks.
Your recipes are always the best!
Good to hear!
Made this Keto Choco Espresso Mousse Cake this past weekend and it turned out great, it was creamy and delicious. It turned out perfect!
This was an absolute chocolate lover’s DREAM! I loved the different layers, it was smooth and creamy, and the brownie base was to die for.
This looks stunning! And thank you for all you do & offer!!
My household is full of thosevthst don’t care for coffee/espresso. Is there a Vanilla bean or raspberry mousse recipe that could be the top layer?
I think you could probably take a thin liquid, such as almond milk or hemp milk, and treat it the same way I use the espresso that top layer. Add a bit of vanilla and there you go!
I have just tried this however I failed with the espresso mousse! I folded in the lukewarm espresso mix in small batches but the mixture curdled – I had liquid coffee & blobs of cream! I still used it & the mixture set plus I whipped up a bit more cream & spread that over the top to cover up the espresso mess on top! Do you have any suggestions or answers as to why this would have separated & curdled please? It tasted divine it just didn’t look good!
What temperature was the espresso at the point where you folded it in? If it was too warm, it could melt the whipped cream. But too cool and the gelatin can start to clump. Also… what gelatin were you using?
Thanks for replying Carolyn. In retrospect I think the espresso was too cool as the cream clumped together – it started off ok but the more I added the more separation took place. I am using an Australian version of the Great Lakes gelatin. As I said it still tastes divine it just doesn’t look as pretty plus the liquid espresso didn’t set as well as the gelatin was concentrated more in the cream. I’ll certainly be trying it again.
Looks great. Will try this shortly. I noticed by the way that in the metric calculation something’s wrong. The heavy whipping cream is noted with 178.5gram for both the chocolate and the espresso layer, but in US it’s different in cups.
Thanks for catching that. Sometimes the automatic conversion doesn’t work properly.
Such an impressive looking dessert!
I need to make this dairy free & don’t want to sub coconut cream, because I don’t want any coconut flavor. I was thinking of using almond milk & giving it a little boost if thickness be adding either 2 oz dairy free cream cheese per cup of milk, or maybe 1/4 tsp gloucomannan power per cup of milk.
You’ll have to experiment here because I don’t see a great way of making this one dairy free without significant adaptation.