Ingredients

1 stick unsalted butter, room temperature

1 cup granulated sugar

1 tablespoon fresh lemon zest

Dash of salt

4 large eggs

1/2 cup freshly squeezed lemon juice (about 4 lemons)

3 large whole eggs

3 large eggs, separated

1 cup plus 2 tablespoons granulated sugar

2 teaspoons lemon zest

1/2 cup freshly squeezed lemon juice (about 4 lemons)

Salt, a pinch

1 cup heavy whipping cream (divided)

1/2 cup homemade lemon curd, room temperature

1/3 cup powdered sugar

1/2 teaspoon pure vanilla extract

Instructions

Step 1: Zest the lemons carefully, avoiding the white pith, and set the zest aside. Juice the lemons and reserve 1/2 cup of juice.

Step 2: In a large mixing bowl, cream the butter using a stand or hand mixer. Add sugar, salt, and lemon zest, mixing well.

Step 3: Crack the eggs into a small bowl and remove the chalaza from each yolk. Add eggs one at a time to the butter mixture, mixing well after each addition. Stir in the reserved lemon juice and salt.

Step 4: Transfer the mixture to a medium saucepan. Cook over low heat, stirring constantly until thickened, about 8–10 minutes. Remove from heat.

Step 5: Spoon the lemon curd into a bowl, cover with plastic wrap placed directly on the surface, and let cool to room temperature.

Step 6: In a heatproof bowl, whisk 3 whole eggs, 3 egg yolks, 1 cup sugar, 2 teaspoons lemon zest, 1/2 cup lemon juice, and a pinch of salt. Place over simmering water and whisk constantly until thickened like pudding, about 12 minutes. Cool for 15 minutes, cover with plastic wrap, and chill in the refrigerator for 1–2 hours until fully chilled.

Step 7: Beat 2/3 of the egg whites with a pinch of salt until soft peaks form. Gradually add 2 tablespoons sugar and beat until stiff peaks form. Carefully fold the egg whites into the chilled lemon filling.

Step 8: In the same mixing bowl, beat 1 cup heavy whipping cream on medium-low speed until it thickens slightly, then increase speed to high until stiff peaks form. Fold the whipped cream into the lemon mixture.

Step 9: Gently fold the room temperature lemon curd into the lemon mixture. Transfer to a souffle dish (about 7-inch diameter x 3-inch deep) and chill for at least 1 hour.

Step 10: To prepare the whipped cream topping, beat cold heavy cream on medium-low until it begins to thicken. Add powdered sugar and vanilla extract, then beat on high until stiff peaks form.

Step 11: Pipe or spoon dollops of whipped cream over the chilled mousse. Optionally, garnish with small quarter lemon slices between the dollops.

Step 12: Serve the mousse cold. Refrigerate leftovers for up to 5 days. Freeze any extra mousse for up to 3 months, adding whipped cream only once thawed and ready to serve.

Tips & Variations

Use fresh lemons for the brightest flavor, and avoid the white pith in zest to prevent bitterness.

For a decorative touch, add fresh berries or mint leaves alongside the whipped cream topping.

If you prefer a less tangy mousse, reduce the lemon juice slightly or add a bit more sugar to balance acidity.

Make the lemon curd ahead of time to save preparation time on the day you serve the mousse.

FAQs

Can I use bottled lemon juice instead of fresh lemons?

Fresh lemon juice is recommended for the best flavor and brightness, but in a pinch, bottled lemon juice can be used. Just be sure to choose a high-quality, pure lemon juice without additives.

Is it safe to eat mousse with raw eggs?

This recipe involves gently cooking the egg mixture over simmering water, which thickens and somewhat cooks the eggs. However, if you are concerned about raw eggs, use pasteurized eggs for added safety.