Triple Lemon Mousse Cake

Triple lemon mousse cake starts with a layer of lemon chiffon cake. The lemon chiffon cake is then topped with a layer of lemon mousse. Finally it is finished with a layer of lemon curd. This cake is a lemon lover’s dream. Every single layer is filled with lemon flavor. Each layer is also light and tender, but at the same time it is creamy and lemony. It’s light, it’s bright, it’s everything a lemon cake should be.

Components of the triple lemon mousse cake:

1. Lemon Chiffon Cake: The cake starts with a lemon chiffon cake base. It is a light chiffon cake layer that is baked in a springform pan. We flavor the cake with lemon juice and lemon zest. This layer is light, tender, and filled with lemon flavor. 
2. Lemon Curd: The lemon curd gets used in two places. We use it within the lemon mousse to give it a creamy, bright, lemon flavor and also on top of the cake. The mousse is made on the stove top in a double broiler. It is made with lemon juice, eggs, sugar, salt, and butter. We will happily just eat this by the spoonful and it is really what makes this cake so incredible.
3. Lemon Mousse: The cakes main layer is a lemon mousse layer. The mousse is made by folding together whipped cream and lemon curd. It’s light and creamy with a more subtle lemon flavor than the curd by itself. 

Triple Lemon Mousse Cake FAQ

Triple Lemon Mousse Cake Ingredient Notes:

1. Cake Flour:
Cake flour is used in the lemon chiffon cake to create a lighter and more tender crumb. If you don’t have cake flour on hand, you can make a DIY substitute by replacing two tablespoons of all-purpose flour with cornstarch for every cup of flour used.

2. Gelatin:
Unflavored gelatin is used to stabilize the lemon mousse and help it set. Make sure to dissolve the gelatin completely in warm water before adding it to the mousse to prevent clumping.

3. Lemon Zest:
The lemon zest adds bright citrus flavor to both the lemon cake and lemon mousse. Be sure to zest the lemons carefully, avoiding the bitter white pith, for the best flavor.

4. Salted Butter:
Salted butter is used in the lemon curd for added richness and flavor. If you prefer, you can use unsalted butter and adjust the amount of salt to taste.5. Heavy Cream:
Heavy cream is whipped to stiff peaks and folded into the lemon curd to create the light and airy lemon mousse layer. Make sure the heavy cream is very cold before whipping for best results.

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Triple Lemon Mousse Cake

Prep Time 1 hour hour

Cook Time 1 hour hour

Servings 8

Ingredients

Lemon curd:

• 1/2 cup Meyer lemon juice
• 3 large eggs
• 1 large egg yolk
• 3/4 cups sugar
• 1 pinch salt
• ½ cup salted butter

Lemon Mousse:

• 2 cups heavy cream
• 1 cup powdered sugar
• Zest of 1 lemon
• 7 grams unflavored gelatin 1 envelope
• 2 tablespoons water

Lemon Cake:

• ¾ cup cake flour 90 g
• ⅓ cup sugar 70 g
• ¼ teaspoon salt
• 1 teaspoon baking powder
• 1 egg
• ⅓ cup lemon juice
• 2 tablespoons oil
• 4 egg whites
• ¼ teaspoon cream of tartar
• ¼ cup sugar 50 g
• Zest of 1 lemon

Instructions

Lemon Curd:

• In a saucepan that a bowl can sit on top of or a double broiler, pour about 2 inches of water and bring it to a simmer. (The bowl should be able to sit on top without touching the water)
• In a bowl, add lemon juice, eggs, egg yolks, sugar, and salt. Place the bowl on the saucepan and whisk the curd continually until the mixture becomes very thick this will take about 10-12 minutes (or it is 180° F on a thermometer.)
• Remove the bowl from the saucepan and cool until it reaches 140° F, stirring from time to time to release the heat.
• While it is cooling, cut butter into 1-tablespoon cubes. When the cream is ready, whisk in the butter 1 tablespoon at a time, stirring until melted after each piece.
• Once all the butter is added, the curd will be pale yellow and thick.
• Place a piece of plastic wrap on top of the curd (directly touching the curd) so no curd is exposed. Let the curd cool in the fridge.
  

Lemon cake:

• Preheat the oven to 350 F.
• Line a 9 inch springform pan with parchment and cooking spray and set aside
• Sift together the flour, ⅓ cup of the sugar, baking powder, and the salt into a medium bowl.
• Add the egg, lemon juice, and oil. Mix until smooth. Set aside
• Add the egg whites to the large mixing bowl and beat until frothy. Add the cream of tartar and continue beating until the egg whites form soft peaks. Add the remaining ¼ cup of sugar and beat until stiff, glossy peaks form. Add the lemon zest and beat just until incorporated, about 15 seconds.
• Using a rubber spatula, fold the egg whites into the batter mixture
• Pour the batter into the prepared pan. Bake for about 30 minutes, until it is just golden brown and a toothpick inserted in the center comes out clean.
• Let the cake cool completely on a cooling rack, about 30 minutes

Lemon Mousse:

• Once both the lemon cake and lemon curd are completed and cooled, prepare the lemon mousse. Start by adding the heavy whipping cream into a large bowl or base of a stand mixer. Whip on medium high speed for about 2-3 minutes until stiff peaks form.
  
• Set aside ½ cup of lemon curd for the top of the cake and add the remaining lemon curd to the whipped cream. Whip together on medium high speed for 30 seconds until well combined.
  
• To prepare the gelatin add the gelatin and room temperature water to a small microwave safe bowl. Microwave for 45 seconds, string every 15 seconds. The gelatin powder should be entirely dissolved.
• Quickly pour the gelatin into the mousse and mix on medium high speed for 1 minute until it is smooth and evenly combined. It is critical to do this step quickly, pouring in the gelatin the minute it is dissolved and still hot or it will clump.

Assembly:

• Run your knife around the cake to help separate the cake from the springform pan
• Pour the whipped lemon mousse over top and spread in an even layer
  
• Allow to set in the fridge for at least 2-3 hours
  
• Top with the remaining ½ cup lemon curd and serve