Triple Chocolate Mousse Cake Recipe

Prepare crust

Preheat oven to 350°F (175°C). Combine crushed graham crackers, toasted chopped slivered almonds, granulated sugar, and salt in a bowl. Stir in melted butter until mixture holds together when pressed.

Press the crumb mixture evenly into the bottom (and slightly up the sides if desired) of a 9-inch (23 cm) springform pan or a removable ring on a baking sheet lined with parchment. Use the bottom of a measuring cup to compact tightly.

Bake crust for 8–10 minutes until set and aromatic. Remove and cool completely on a wire rack. Reduce oven to 300°F (150°C) if you like to warm the pan slightly before assembling (optional).

Bloom gelatin

Sprinkle 1 tsp gelatin over 2 tbsp cold water in a small bowl. Let sit 5–10 minutes to bloom.

Melt chocolate

Place chopped dark chocolate and butter in a heatproof bowl set over a simmering water bath (double boiler) or microwave in 20-second bursts, stirring until smooth. Remove from heat and let cool slightly.

Make zabaglione

In a heatproof bowl whisk together 4 egg yolks and 2 tbsp sugar. Set bowl over a pot of simmering water (bain-marie) and whisk continuously until the mixture is pale, thick, and ribbons form—about 4–6 minutes. Remove from heat.

Whisk the bloomed gelatin into the warm zabaglione until dissolved. Gradually stream the melted dark chocolate into the zabaglione, whisking to create a smooth, glossy chocolate custard. Taste and adjust sweetness if needed.

Fold in whipped cream

Whip 1.25 cups cold heavy cream to soft peaks. Fold one-third of the whipped cream into the chocolate custard to lighten, then gently fold in the remaining cream in two additions until homogeneous and airy. Avoid overfolding.

Spoon or pipe the dark chocolate mousse over the cooled almond crust, smoothing the top. Place pan in freezer or refrigerator to firm for 20–30 minutes while preparing the next mousse layer.

Bloom gelatin

Sprinkle 3 tsp gelatin over 3 tbsp cold water in a small bowl. Let sit 5–10 minutes to bloom.

Heat milk and sugar

In a small saucepan, heat 1 cup whole milk with 2 tbsp sugar until just steaming but not boiling.

Temper yolks

Whisk 3 egg yolks in a bowl. Gradually pour one-third of the hot milk into the yolks while whisking constantly to temper. Return tempered yolk mixture to the saucepan and cook over low heat, stirring, until it slightly thickens and coats the back of a spoon (do not boil). Remove from heat.

Stir bloomed gelatin into the warm custard until dissolved. Pour the warm custard over the chopped milk chocolate and let sit 1–2 minutes, then stir until fully melted and smooth.

Fold in whipped cream

Whip 1 cup cold heavy cream to soft peaks. Fold one-third into the milk-chocolate custard to lighten, then fold in remaining cream gently until uniform.

Carefully spread the milk chocolate mousse over the chilled dark chocolate layer, smoothing the surface. Chill for 30 minutes to firm before adding the final layer.

Bloom gelatin

Sprinkle 2 tsp gelatin over 2 tbsp cold water in a small bowl. Let sit 5–10 minutes to bloom.

Heat milk and sugar

Warm 3/4 cup whole milk with 1 tbsp sugar in a small saucepan until steaming.

Temper yolks

Whisk 2 egg yolks in a bowl. Slowly add a small amount of hot milk while whisking, then return to saucepan and cook over low heat until it slightly thickens (do not boil). Remove from heat.

Stir bloomed gelatin into the warm custard until dissolved. Pour over chopped white chocolate and let rest 1–2 minutes, then stir until completely smooth. If white chocolate resists melting, warm briefly over a double boiler while stirring.

Fold in whipped cream

Whip 3/4 cup cold heavy cream to soft peaks. Fold one-third into the white-chocolate custard to lighten, then fold in remaining cream gently until smooth and airy.

Spread the white chocolate mousse evenly over the chilled milk-chocolate layer. Smooth the top. Refrigerate the assembled cake at least 4 hours, preferably overnight, to fully set.

Make glaze

Place 4 oz chopped dark chocolate in a bowl. Heat 1/2 cup heavy cream until it just begins to simmer, then pour over the chocolate. Let sit 1 minute, then stir until smooth. Stir in 1 tbsp butter until glossy. Allow glaze to cool slightly until pourable but not hot (about 10–15 minutes).

Unmold the chilled mousse cake from the springform. Place on a wire rack over a baking sheet. Pour glaze over the center of the cake and tilt to allow it to spread and drip down the sides. Use an offset spatula to nudge glaze to edges if necessary.

Transfer cake to serving plate. Dust top lightly with cocoa powder and scatter chocolate shavings or curls around the top edge. Return to refrigerator for 15–30 minutes to set the glaze.

Slice with a hot, dry knife (dip in hot water and wipe dry between cuts) for clean slices. Serve chilled. Leftovers keep refrigerated for up to 3 days.