Luscious lemon mousse cake might be the perfect layer cake. Lemon cake with Limoncello syrup, zesty lemon curd and creamy lemon mousse. (Limoncello liquor is optional.)
I am so excited to share this recipe with you! For many years this was the most popular cake flavor for my custom cake business. Once I introduced the Chocolate Chip Cookie Cake the two cake flavors shared top billing.
For the last 5 years I’d say almost half the wedding cakes I sold had two different flavors in the cake; half the servings with the cookie flavor, and the other half with Luscious Lemon Mousse Cake. And this cake is truly luscious!
Yes, this cake is a little bit of a project. But I think it’s totally worth the effort, especially for a special occasion.
If you watch the video you’ll see the entire process. It is sped up, but you can see how easily the whole thing comes together once you have all the components in place.
How to make a great Lemon Mousse Cake:
The step that might be the most unfamiliar to non-pastry-chefs is how to “liason” or “temper” the gelatin into the mousse.
Tempering gelatin is similar to the process for tempering eggs into hot milk to make custard.
If you simply poured the warm gelatin into the cool mousse it might immediately set into little rubbery lumps. Definitely not the texture we’re going for here.
By whisking a scoop of mousse into the melted gelatin we bring the two ingredients closer together in texture and temperature. Now we have silky-smooth mousse. The filling is set with just enough gelatin to hold it together when the cake is sliced.
The limoncello makes the flavor extra special. Of course, if you can’t or don’t want to do liquor you can leave it out. You can use water to bloom the gelatin.
But even if you generally aren’t a fan of liquor flavors I suggest you give it a try. The limoncello adds a deep lemon flavor without leaving a boozy aftertaste. You can check out this post to see why alcohol enhances flavor.
This cake recipe incorporates several other recipes. There is no need to reinvent my cake and buttercream recipes every time I come up with a new flavor. I just flavor them to whichever cake I’m putting together. All the recipes are linked in the recipe card.
If you want to try making a “Lemon Meringue” variation of this cake, you can ice the cake with Seven Minute Frosting instead of the meringue buttercream. Use a blow torch on the seven minute frosting for a lovely toasted finish.
Watch the recipe video to see how-to make a Luscious Lemon Mousse Cake from start to finish.
If you love great cake recipes, you’ll love my new book: Easy Baking From Scratch: Quick Tutorials, Time-Saving Tips, Extraordinary Sweet and Savory Classics. The book contains over 100 recipes that have been well-tested and are presented in simple, clear language. It’s available now on Amazon.
Want to learn more about how I create my cake recipes? This post has lots of great information about baking science and how to perfect any recipe.
Now that you’ve mastered this spectacular cake, you might want to give this Key Lime Layer Cake a go. It’s another stunner!
If you love this recipe as much as I do, I’d really appreciate a 5-star review.
Luscious Lemon Mousse Cake
Luscious lemon mousse cake might be the perfect layer cake. Lemon cake with Limoncello syrup, zesty lemon curd and creamy lemon mousse. (Limoncello liquor is optional.)
Ingredients
Cake
- 1 recipe Vanilla Butter Cake
- Grated zest from 1 lemon
- 2 teaspoons lemon extract
Lemon Mousse
- 3 tablespoons (1.5 oz, 44ml) Limoncello (use water if you want to avoid alcohol)
- 1 teaspoon lemon extract
- 1 1/2 teaspoons gelatin powder
- 1 cup (8 oz, 236ml) heavy cream
- 2 tablespoons powdered sugar
- 1 1/4 cups Lemon Curd
Assembly
Instructions
Cake
- Mix the cake according to the recipe, adding the zest to the dry ingredients and the lemon extract with the vanilla.
- Divide the batter between two 8" pans lined with a parchment round or buttered and floured. Bake as instructed in the recipe. Wrap the cooled layers and chill until firm (I like to bake the cake a day ahead)
- When you're ready to assemble the cake, trim the browned edges and domed top off both cakes. Split each cake horizontally so you have a total of 4 cake layers. See how to prep the layers here. Have your syrup and buttercream ready before you begin making the Lemon Mousse.
Lemon Mousse
- Place the Limoncello (or cold water) and lemon extract into a microwave safe bowl. Sprinkle the gelatin over the liquid in an even layer. Whisk briefly to combine and set aside to bloom. Whip the cream with the powdered sugar and set aside.
- Place the 1 1/4 cups lemon curd in a large mixing bowl and use a spatula to smooth out the curd to break up any lumps. Fold 1/3 of the the cream into the lemon curd until no lumps of curd remain. Fold in the remaining cream until it's about 1/2 way incorporated.
- Heat the bloomed gelatin in the microwave in 10 second increments until it's hot to the touch. Working quickly, add a 1/2 cup of the mousse to the warmed gelatin. Whisk immediately until completely incorporated. Pour the gelatin mixture back into the mousse. Immediately whisk until the mousse is smooth and the gelatin is evenly incorporated. If the mousse is very soft, refrigerate briefly to let it thicken before assembling the cake.
Assembly
- Fill a piping bag fitted with a star tip with buttercream (or use a disposable bag with the tip cut).
- Set one layer of the cake, flat side down, onto a cardboard cake round or a serving plate. Brush the layer generously with the Limoncello syrup. Pipe a ring of buttercream around the edge of the layer to form a "dam" for the mousse. Scoop half the lemon mousse onto the layer and smooth until even.
- Gently place the second cake layer onto the mousse, careful not to squish the mousse layer. Brush the layer with syrup and pipe a dam of buttercream. Set aside a 1/2 cup of the lemon curd and scoop the rest onto the layer. Smooth the curd until even (be careful not too press hard or you might squish the mousse layer beneath).
- Place the 3rd cake layer, brush with syrup and pipe a dam. Fill with the remaining lemon mousse. Top with the 4th layer, brush with syrup. Set the cake into the refrigerator for about 20 minutes to set the buttercream "dams" and the mousse.
- Ice the cake with a thin crumb coat of buttercream. Refrigerate the cake for at least an hour to set the buttercream and allow the mousse time to gel. Ice the cake with a final coating of buttercream.
- Use a piping bag fitted with a star tip to pipe a border around the top of the cake. Spread the last 1/2 cup of curd onto the cake. Refrigerate for at least 3-4 hours to make sure the filling is completely set, preferably over night.
- Remove the cake from the refrigerator 1/2 hour before serving.
Notes
The cake must be stored in the refrigerator because of the mousse filling. Take the cake out 1/2 hour to an hour before serving to allow it to soften before serving. Leftovers can be refrigerated and the cake freezes very well.
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Denise
Monday 24th of October 2022
where is the video for this recipe ? please
Eileen Gray
Monday 24th of October 2022
If you have an ad blocker on the video won't play. Turn off your ad blocker and you'll see the video.
Jessie
Friday 23rd of September 2022
Can you make the mousse the day before?
Eileen Gray
Friday 23rd of September 2022
Yes. It will set up because of the gelatin, so you'll have to work it a little to spread it onto the layers.
Sue C.
Sunday 24th of April 2022
All I can say is WOW! I missed any cake for my 60 or 61 birthday due to the pandemic, so this year we ordered a lemon cake. We couldn’t even eat it, it was just not good and it made me really sad, a lot of money wasted. I will be making my own cake now and it will be from this recipe! This is exactly what I was hoping for! Thank you!
Steffanie
Monday 11th of April 2022
I love your blog!! My 9 year old son is obsessed with poke cakes and has asked for another one for his birthday this year. Because this curd is stabilized with gelatin, do you think I could poke holes with a wooden spoon part way down my cake layers and then pour warm curd into the cake and then refrigerate to set? I am very tired of the usual artificial jello flavors and want something special this time ;)
Eileen Gray
Monday 11th of April 2022
I think that should work.
Anne
Wednesday 30th of March 2022
Hello! I made this cake and it was delicious and moist. Had to make two batches of frosting. I had one question. It says you can prepare the lemon curd beforehand. Does this mean even with the gelatin in it. Or do you prepare the lemon curd beforehand bring it back to room temperature and then add the gelatin right before assembling the cake?? I ended up making the cake in one day which took awhile but it turned out great! Thank you for sharing this recipe!
Eileen Gray
Wednesday 30th of March 2022
You can make the lemon curd with gelatin ahead of time. I find that if you bring it back to room temperature and then stir it with a spatula to loosen it up it's pretty easy to spread. You could also warm it briefly in the microwave and stir. Even if you overdo it and it becomes too soft just chill it again until it's spreadable. I also have frozen lemon curd with gelatin with great success.