This decadent Mary Berry Chocolate Mousse Cake is made with a rich chocolate sponge base and a light-as-air chocolate mousse using quality dark chocolate, whipped cream, and eggs. The result is an elegant and impressive dessert with a velvety smooth texture that simply melts in your mouth. It’s the perfect showstopper for a dinner party or special celebration and this recipe makes a stunning dessert for 8-10 people.

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Mary Berry Chocolate Mousse Cake Ingredients

For the Chocolate Sponge Base:

4 tbsp unsalted butter, softened, plus extra for greasing
¼ cup caster (superfine) sugar
1 large egg
⅓ cup self-raising flour
2 tbsp unsweetened cocoa powder

For the Chocolate Mousse:

7 oz good-quality dark chocolate (at least 70% cocoa solids), broken into pieces
3 tbsp unsalted butter
3 large eggs, separated
¼ cup caster (superfine) sugar
1 ¼ cups double (heavy) cream

For Decoration (optional):

Chocolate shavings or curls
A dusting of cocoa powder

How To Make Mary Berry Chocolate Mousse Cake

Make the sponge base: Preheat your oven to 350°F (180°C / 160°C Fan). Grease an 8-inch (20cm) round springform tin and line the base with parchment paper. In a bowl, beat the butter, sugar, egg, flour, and cocoa powder together until smooth. Spoon the mixture into the prepared tin, level the top, and bake for 20-25 minutes until risen and firm. Let it cool completely in the tin.
Melt the chocolate: To make the mousse, gently melt the dark chocolate and butter together in a large heatproof bowl set over a pan of barely simmering water (this is called a bain-marie). Make sure the bottom of the bowl does not touch the water. Once melted and smooth, remove from the heat and let it cool for about 10 minutes.
Incorporate yolks and cream: Beat the egg yolks and sugar into the cooled chocolate mixture until well combined. In a separate bowl, whip the double cream until it holds soft peaks. Gently fold the whipped cream into the chocolate mixture using a large metal spoon, being careful not to knock out the air.
Fold in the egg whites: In another spotlessly clean bowl, whisk the egg whites until they form stiff, glossy peaks. Carefully fold the egg whites into the chocolate mixture in two batches. The first batch can be mixed a bit more to loosen the chocolate, but the second should be folded very gently until just combined.
Assemble and chill: Pour the finished chocolate mousse over the cooled sponge base still in the springform tin. Smooth the top with a spatula. Place the tin in the refrigerator and chill for at least 4 hours, or preferably overnight, until the mousse is firm and completely set.
Decorate and serve: To serve, run a thin knife around the edge of the tin before carefully releasing the springform clip. Decorate the top with chocolate shavings or a dusting of cocoa powder, if desired.

Recipe Tips

Use Good Quality Chocolate: The flavor of this dessert is defined by the chocolate. For a deep, rich taste, use the best quality dark chocolate you can find, with at least 70% cocoa solids.
Gentle Folding is Key: The light, airy texture of the mousse comes from the air you whip into the cream and egg whites. To preserve this, you must fold them into the chocolate base gently. Use a large metal spoon in a slow figure-eight motion to combine the ingredients without losing volume.
Let the Chocolate Cool: Ensure the melted chocolate mixture has cooled to lukewarm before you add the egg yolks and whipped cream. If the chocolate is too hot, it can scramble the eggs or cause the whipped cream to melt and deflate.
Allow Adequate Chilling Time: Don’t be tempted to rush the chilling process. The mousse needs several hours in the refrigerator to set properly so that it holds its shape beautifully when you slice the cake. Chilling overnight is ideal.

What To Serve Chocolate Mousse Cake

This chocolate mousse cake is a rich and complete dessert that needs very little accompaniment. It is best served chilled, straight from the refrigerator. To balance the intense chocolate flavor, a tart fruit component works beautifully. Serve each slice with a few fresh raspberries or a drizzle of a sharp raspberry coulis.

How To Store Chocolate Mousse Cake Leftovers

Refrigerate: This cake contains fresh cream and uncooked eggs, so it must be kept refrigerated. Store any leftovers in an airtight container in the refrigerator and consume within 2 days.
Freeze: Freezing is not recommended for this dessert. The delicate, airy structure of the mousse can be damaged by ice crystals, causing it to become grainy or watery upon thawing. This cake is best enjoyed fresh.

Mary Berry Chocolate Mousse Cake Nutrition Facts

Serving size: 1 slice (1/10th of cake)
Calories: 545 kcal
Total Fat: 45g
Saturated Fat: 26g
Sugars: 28g Sodium: 120mg
Total Carbohydrate: 30g
Protein: 9g

Frequently Asked Questions

Is it safe to eat the raw eggs in the mousse? This recipe contains uncooked eggs. To minimize risk, it is important to use the freshest eggs possible from a reputable source. In some countries, like the UK (look for the British Lion mark), eggs are produced under a scheme that vaccinates hens against salmonella. In other regions, if you have concerns, it is safest to use pasteurized eggs, which are available in cartons at most supermarkets.
My mousse seems too runny and didn’t set. What went wrong? The most common reason for a mousse not setting is that it wasn’t chilled for long enough. It truly needs at least 4 hours, and overnight is even better. Another possibility is that the mousse mixture was over-mixed when folding, which can cause the airy structure to collapse.
Can I make just the mousse part of the recipe? Absolutely. The chocolate mousse is a fantastic dessert on its own. You can skip the cake base entirely and simply spoon the finished mousse mixture into individual serving glasses or ramekins. Chill them until set for an elegant and easy dessert.

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