With a small tweak of the ingredients—that is, the addition of butter (or a dairy-free substitute) and some sugar—this mousse al cioccolato can be turned into a superb flourless chocolate mousse cake that’s perfect for Passover. I have yet to find someone who doesn’t go crazy for this cake at the first bite. What makes the cake so special is its texture: The egg whites make the base of the cake fluffy, like a chocolate pillow, and the top of the cake is rich and creamy, thanks to the egg yolks.
If you’re pregnant or want to avoid eating uncooked eggs for another reason, you can buy pasteurized egg whites and use regular egg yolks, but “pasteurize” them at home with the chocolate. It’s easy: Just cook the egg and chocolate mixture over very low heat, stirring constantly, until a candy thermometer reads 149°F (65°C), then set aside to cool before proceeding. To get pasteurized egg whites to form stiff peaks, add a splash of lemon juice or a pinch of cream of tartar to the bowl.
Recipe information
Yield
Makes one 9-inch cake
Ingredients
Preparation
Step 1
Preheat the oven to 350°F (180°C). Line the bottom of a 9-inch (23-cm) springform pan with parchment paper.
Step 2
Break up or chop the chocolate and place it in a heatproof bowl with the butter or margarine. Set the bowl over a saucepan of barely simmering water and allow the chocolate and butter to melt, stirring occasionally. When everything has melted, remove from the heat and let cool to room temperature.
Step 3
In the meantime, put the egg yolks in a large bowl. In the bowl of a stand mixer fitted with the whisk attachment, or in a large bowl, using a handheld mixer, whip the egg whites to very firm peaks, about 5 minutes.
Step 4
When the melted chocolate mixture has cooled, add it to the egg yolks, along with the sugar, and whisk well.
Step 5
Using a rubber spatula, stir about one-third or less of the egg whites into the chocolate mixture to lighten it. Carefully spoon another third of the egg whites on top of the chocolate mixture and gently fold them in. Add the remaining whites and fold them in just until incorporated.
Step 6
Transfer half of the batter to another bowl and set aside in the refrigerator.
Step 7
Pour the remaining batter into the prepared pan and bake for 20 minutes: it will turn into a soft, moist cake. Remove from the oven and let cool completely in the pan.
Step 8
When the cake has reached room temperature, pour the reserved chocolate mousse on top of it. Refrigerate the mousse cake, uncovered, for at least 2 hours, or overnight, until set.
Step 9
When you’re ready to serve, run a sharp thin-bladed knife around the cake’s edges and then remove the sides of the springform pan. Peel the paper from the bottom, and place the cake on a serving platter. Serve cold, decorated with chocolate shavings, if desired.
Step 10
Leftover cake will keep in the refrigerator, wrapped in aluminum foil, for a couple of days.
Recipe notes
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37 Passover Desserts to End Your Seder on a Sweet Note
Coconut macaroons, matzo toffee, and so much more.Is This Magical Chocolate Dessert a Mousse or a Cake?
Spoiler alert: It’s both. This easy, luscious chocolate mousse becomes a Passover-friendly dessert with just two more ingredients: butter and sugar.
